Some parents consider their dependents nothing more than a cash cow they can exploit for personal gain. Either the parents take the money a child earns and keep it for themselves, or they actively deny the dependent personal gain.
This can also exist in a separate form, by withholding support unless they obey all of the parent's wishes, no matter how cruel or unreasonable, without complaint. Abuse is about control, and this is controlling them through money. Bonus points if the parents are foster parents, and keep the kids around for the welfare check.
Very much Truth in Television, and enters the media spotlight regularly when one or both parents of a rising young music or acting star exploit their child's achievements. This is the reason for the Jackie Coogan Act, named after the child actor whose parents blew through most of his money—around three-four million, back in the 1920s and '30s.
This form of abuse also exists between spouses/partners, either when one member of a couple exploits the other financially (stealing their savings, taking out unauthorized credit lines or loans in their name, and making unauthorized and often unwise or fraudulent investments are some common methods of doing this) or when they deprive the other of access to money, often as a way to keep an abused spouse from escaping. It's also frighteningly common for adult children to financially abuse elderly relatives, especially those with cognitive disabilities.
Finally, another form of it is combined with religious abuse: a religion or sect or guru demands monetary donations or time that could be spent elsewhere to the extent that the donations or lifestyle damages the givers' financial well-being, and/or demands exorbitant donations for advancing in the religious system, faith healing, initiations, or similar. The Church of Happyology is infamous for this, but there have been many other less well-known examples too.
A subtrope of Abusive Parents and Domestic Abuse.
Common plot element in Gunslinger Girl, Angelica in particular. She had her parents collude to make it look like she was in a hit-and-run "accident" so they could cash in on the insurance money to pay off some debts, and it was her father who ran her over with his own car. The badly-injured Angelica ended up taken in by the Agency, which made her into a Cyborg.
There is a one-shot manga by this author that opens with a son trying to escape from his parents, since they keep trying to use his bone marrow to create gold and thus solve their financial woes.
And there's also the series Rinne, in which the main character Rinne gets this so bad from his Jerkass father that it's hard not to be horrified despite it being Played for Laughs.
Also, Genma Saotome from Ranma ½ has pawned his son Ranma off more than once to get material benefits.
Yuki Sohma from Fruits Basket suffered such a fate from his Control Freak mother, who even sold him out to Akito to make herself look better in the Sohma clan. His brother Ayame apparently used to get it too, pretty much running away from the household as soon as he could (which Yuki couldn't forgive him for, since it left him alone with their mom). Later, however, Ayame gets a Crowning Moment Of Awesome by calling out their mom in public during a school meeting, and it's implied that things may have started to slowly get better.
Maria Wong from Yami No Matsuei, being an Idol Singer, was nothing more than a cash cow to her mother. To the point that when Maria got fed up and commited suicide, Mrs. Wong hired Dr. Muraki to revive her. Which he did... but poor Maria ended up as a Tragic Monster instead. At the end of the case, when everything's resolved, Maria asks Tsuzuki and Hisoka to wait for her for a single night so she can give her last concert, and before that she takes the chance to call out her mom.
Implied in the Lucky Star anime. Akira, former child star and still sort-of popular, mentioned that her mother did have some very nice purses and such that certainly weren't there yesterday...
Many, MANY cases in Detective Conan have elements of this. There are two forms: someone kills or attempts to kill another person to collect their insurances/inheritances and ends up thwarted by Conan; or somebody else kills an Asshole Victim to punish them for driving a friend/relative to suicide or murder via financially abusing them.
Mwu La Flaga from Gundam SEED was a victim of this, after his father Al Di Flaga cut him off his inheritance and locked him away merely for being too much like his mother. Al then went and cloned himself, with said clone growing up into Rau Le Creuset.
Sakuya Ookochi from Sensual Phrase gets this from his Parental Substitute. He originally was his Missing Mom Reiko's sponsor and when she died, she left a huge debt behind; noticing that young Sakuya had inherited his mom's physical beauty and musical talents, he raised Sakuya to be a good musician so he could Work Off the Debt, but gave him no moral or emotional guidance.
One Sandman story has this, the abusive (foster) parents keep the kid locked in the basement so they can receive child support, taking him out only when the health inspection comes around. Though it is implied that they were driven insane by a pair of nightmares living in the boy's mind, who needed an abuse victim who has completely shut his mind from his environment to provide them a hiding place.
Lady Cecilia from Yoko Tsuno's short story The Prey and the Shadow is apparently The Ophelia, locked away from the world in a Scottish castle while her uncle and stepfather William handles the family business. However, the truth is very much this: Cecilia is sane but very naive due to years of isolation, William is planning to kill her for her deceased mother Mary's inheritance and make it look like she fell into despair and was Driven to Suicide to be Together in Death with her Missing Mom. (Not to mention, he staged poor Mary's death). The Cecilia seen at the beginning was a Body Double named Margaret, whom William also financially abused via forcing her into collaborating via Black Mail... and she ends up derailing his cruel gambit by confirming Yoko's bad feeling about the whole deal and asking her for help to save both of them.
In the original Captain Marvel's origin story, young orphan Billy Batson is living hand to mouth because, after his parents died & left him a small fortune, his evil uncle/legal guardian kept the money and threw Billy out to live on the streets.
The teenaged girl Babydoll was put in a mental institution at the start of Sucker Punch by her stepfather, who wanted the girl's large inheritance.
A scam in The Glass House (2001) also counts. Ruby and Rhett, the two protagonists, were adopted by friends of their dead parents, Erin and Terry... only to be targetted for death so the "new parents" can collect their huge inheritance money. (Not to mention Terry makes passes at Ruby, who's squicked outta her mind... and then she finds out that both he and Erin staged the parents's deaths.) Plucky Girl Ruby has to pretty much kill Terry to save herself and Rhett (Erin was Driven to Suicide out of guilt a while before), and then the kids are taken in by their uncle.
Jimmy MacElroy's father in Blades of Glory adopts talented orphans. He unadopts him after he's banned from competition.
A variant occurs in Taking Woodstock. Elliot's mother is constantly nagging him to the point of emotional abuse to put his savings and time into her failing motel. This is despite the fact that she has close to $97,000 hidden in the floorboards which she refuses to share with anyone or invest in her own business
In In Time, time is literally money, with people acquiring a year on their 25th birthdays, spending and earning it like money. Many parents in this world eagerly wait for their children to turn 25 to use their allotted year to pay off their debts. When a person's countdown hits 0, he or she dies instantly. The protagonist, Will, had this happen to him by his mother and wound up with a little over a week to live; he's spent his days living from paycheck to paycheck to survive. He's not resentful about it, though, and his mother is depicted as being generous (a fact which gets her killed).
Secondhand Lions: Walters mom left him with his two crazy uncles to spy on them to find their large stack of money, and the two also get hounded by golddigging relatives.
In the Body Of Christopher Creed the mother of the title character kept track of every bit of money he earned. His ace in the hole was hiding $100 to use when he finally leaves town as food and fare money.
In Franz Kafka's The Metamorphosis, Gregor was the sole financial provider for his parents and family, and whether they were actively abusing this is difficult to tell.
Given that it's implied that they'll exploit Grete now that her fortunes are better...
Harper's mother in the Greywalker series is revealed to be the reason Harper was a professionally trained dancer from a single-digit age, and eventually an "aspiring" actress, and the main reason she became a self-employed per-case contract detective (having vowed never to let someone else be her boss).
An inversion in The Bible when Jesus criticized the practice of dedicating property to the temple to avoid taking care of one's parents. Presumably this was either because of spite or because of a loophole that allowed the owner to use the property while not owning it, thus having his cake and eating it too.
In Maximum Ride, Gazzy was sold to the School for 10,000 dollars.
The Mysterious Benedict Society has George "Sticky" Washington, whose parents were somewhat poor. Upon discovering that he had a photographic memory and had absorbed the contents of an entire encyclopedia, they began entering him in quiz competitions to earn money and placed increasing pressure on him. After he ran away, though, they became deeply regretful and spent all of the money and more to find him, going deeply into debt. After they are reunited with him, they spend most of the rest of the trilogy atoning for what they did.
In A Series of Unfortunate Events, a misunderstanding puts three orphaned children under the care of the ruthless Count Olaf who is intent on using his guardianship to steal their fortune. This runs the gamut from depriving them of basic needs to attempting to marry the oldest child - an underage girl - in order to get access to the money immediately.
There are multiple Sherlock Holmes short stories which involve men who are either taking financial advantage of a woman's property or trying to get into a position where they can do so.
In Unseen Academicals, Juliet's family seem to be a mild case based on stupidity rather than malice; Mr. Stollop demands that all family earnings are "pooled", but Juliet says he spends most of it at the pub. It doesn't help that only Juliet spends a lot of time working; her brothers are all football hooligans. Thankfully, when she makes fifty dollars from modeling in a fashion show, she has Glenda to hide the money.
In one of The Cat Who books, one of the prominent families in Moose County is said to control their adult children by "giving [the kids] a taste for luxuries but keeping them poor."
A minor character in The Gates of Sleep was a child chess prodigy whose father forced him to play exhibition games for money until the kid had a nervous breakdown. (After Dr. Pike brings the boy out of it, he teaches the boy how to pretend his breakdown removed his chess skills — meaning the boy won't be abused this way again.)
Eleanor's father's will left everything to her, Alison goofed and didn't make sure the will had been changed before arranging his death. So Alison simply steals every penny sent to support Eleanor.
Live Action Television
In the American version of Shameless, Frank Gallagher often fraudulently opens up credit cards in his kids' names. His oldest daughter, Fiona, confronts him about opening a credit card in the toddler's name.
An episode of Law & Order had parents that took their son to a celebrity's (a not-Michael Jackson) party so he could molest him in return for a large amount of money. They did it for the sake of their youngest son who was ill, but when the oldest son learned that the money wasn't hush money given after the molestation but before, he testified against them.
One episode had white parents set their black adopted child up to be killed by white supremacists to collect the insurance money.
Another SVU episode had the grandmother of a little girl poisoning her in a way that resembled cancer so she could collect and pocket money from various charities, and gain sympathy from people. They also told the little girl to lie and say a famous celebrity (another not Michael Jackson) molested her so they could get a settlement. The same episode had the family of an actual victim of the celebrity making him keep quiet about his rape after they signed a contract with the celebrity that granted them a considerable amount of hush money.
In the series finale Lois ensures Malcolm won't get a very high-paying job without having to go to college. It is only when Malcolm is alone with his parents and he demands an explanation that they reveal throughout his life Malcolm's parents have sought his limit and had never found one. They feel he will one day become President of the United States. Knowing this, they are forcing him to struggle and work his way through college so that he has an understanding of the financial struggles that most people face. Selfish? Yes, but for a greater cause than themselves... unless you realize that his family's financial problems are largely self-inflicted.
Hal and Lois intercept a $10,000 college grant for Malcolm, spend much of it on themselves and give the remainder to Malcolm without his knowing that it had been a much larger amount. True to his family roots, he blows it on fancy senior pictures since he botched his school one.
Lois takes most of Malcolm's paychecks.
At one point, Lois and Hal find out that since Malcolm tests so high on college aptitude tests, some credit card companies offer him free cards and accounts. Malcolm has enough sense to not use them. Hal then steals the cards to pay for a family skiing trip, without Malcolm's knowledge or permission, which he clearly never intends to pay back. And he'll never be able to pay it off. Since the charges were fraudulent, Malcom isn't liable. His father, however, could go to jail for that stunt.
In one episode of Married... with Children, Al and Peggy did this to Bud by accident, thinking the money in the bank account was a banking error in their favor.
A scheme to embezzle money from Child Services using this trope was central to the plot of an episode of Person of Interest.
Happens to Eliot in Scrubs - when she refuses to take the specific medical career path her father has mapped out for her, he instantly cuts off all financial support, leading to her living in a removal van.
Alan suffers from this. His ex-wife Judith got most of Alan's possessions in the divorce, including his house. She also makes him pay ridiculous amounts of alimony and child support, which she spends not on Jake but herself, to get back at him... somehow.
Subverted in later seasons in that Judith has remarried, which relieves Alan of alimony obligations, and that Jake is an adult. This relieves Alan of child support obligations - and since Jake is in the Army, he has a regular paycheck, meaning he's not hitting Alan up for money. It appears that Alan has always been a moocher and the alimony/child support payments were just a convenient way for him to garner sympathy.
Mariana in The Fosters has been selling her brother's ADHD meds to give money to their biological mother who she later complains "treats her like an ATM".
You are put into this role in the Princess Maker games: you are given the task of caring for a 10-year-old girl until she reaches adulthood. The creators have not given any effective means of income, as the player character's salary is a pittance when compared with typical expenses. The salary the ten-year-old girl gets from various odd jobs is your primary way of making money. Apart from necessities (clothes, tuition etc.) you will also use to give her pocket money and birthday presents. All taken from her own paychecks.
Mikwa of Dragon Quest VII stands on the verge of this. A Child Mage-in training, she spends all her time practicing magic because their ruler highly values his magicians, and one of her parents wants to take advantage of this as soon as possible. Her other parent isn't so sure, but isn't able to convince their partner that they should ease up and let Mikwa be a child... until she's nearly incinerated alive by a passing wizard For the Evulz.
Sonic Battle: Rouge planned to use Emerl to help her steal jewels.
Parodied in which an orphan is glad he doesn't have parents because of this trope.
In another episode we found Homer spent all the money Bart earned as a baby from commercials to cover evidence of him dropping Bart off a balcony. Bart then managed to successfully sue for emancipation and won because of it.
In another episode a TV executive adopts a bunch of orphans so he can use them as cheap labor for his children's TV show. It's a subversion since even with the child labor, the orphans are much better off than they were in the orphanage where they were forced to eat books as food. It's a Crapsack World.
Played for rather dark laughs in the Robot Chicken episode where Lindsay Lohanwas aHighlander — her mother is shown asking someone hiring Lindsay to make a check out to "cash," because "that's my nickname for her."
Pete on Goof Troop engages in this variety of abuse with alarming regularity. He repeatedly forces his son, PJ, to do huge amounts of hard manual labor for him and generally either severely underpays him or refuses to pay him at all; though there are a couple of episodes where Pete's willing to pay PJ (and Pistol) somewhat decently, these are the exception to the rule. To avoid losing the profits for one day, he tricked PJ into doing his job while Playing Sick. He repeatedly uses both of his children as free advertising, including pressuring PJ into throwing a spelling bee and skydiving, the latter of which he wouldn't even be willing to do himself, in order to do so. And on top of all of that, he repeatedly spends his children's savings on himself.
In some of the later seasons of Family Guy Peter and Lois can be seen sneaking money from their children's drawers and wallets.
In The Cleveland Show man and his wife were going to adopt Ernie from social service, but when Lester came to reason with the service worker to keep his son, the man adamantly says that they're only in it for the money they would receive and they have a basement full of other foster children who they don't seem to care.
Timmy is subjected to this in an episode of The Fairly Oddparents after his father becomes a farmer. He resorts to trying to get the farm destroyed just so that he won't have to be his dad's unpaid farmhand forever.
When Luna Travoria of Dominic Deegan first appeared, she had undergone years of parental abuse, culminating in a plot to make her commit suicide at a certain time and place - because Luna's mother could expect to receive a financial settlement from the government if Luna died while a royal knight was staying in their home.
A recurring theme in the second season of Tower of God is how several characters had their lives controlled by the Loan Sharks that exploited their situation.