Something bad happens. Or the main character wants to archieve something, or reach somewhere. Either way, there may be an objective to fulfill in the near future. This objective may be the motivation to start an adventure. Not too long afterwards, the character is told about how the objective can be archieved, and it may have to do with the collection of important objects, or the search for characters. This would be the start of a very long and difficult quest, enough to make the quest for the first object or character very difficult on its own.
Fortunately, the first MacGuffin or Plot Coupon appears as soon as the quest starts.
This first encounter is the Free Sample Plot Coupon. It serves as a good motivation to look forward to the remaining objects or characters, which (or who) are genuinely more difficult to find. Now, how the first MacGuffin appears may depend on the plot or the place:
It may be located right next to the main character. Not too shabby.
If it's an object, whoever holds it will appear instantly.
If it's a character, he or she may appear instantly.
Or, by some fortunate coincidence, the character may already have had it all along. Or is the Mac Guffin.
Naturally, if the item or character takes a lot of effort to find (if not more than the others), then it doesn't fit the trope. Not to be confused with This Is Your Premise on Drugs.
Anime and Manga
Dragon Ball, for the most part, revolves around looking for the Dragon Balls. Fortunately, Son Goku already has one at the start of the series, and Bulma meets him having two, making the quest much easier already.
Downplayed in InuYasha. Kagome already has the Shikon pearl inside her at the start of the series, but after some unsavory events it is fragmented into several pieces, scattered through Feudal Japan. Thus the objective is to retrieve them, and the first of them is held by a very powerful opponent, negating the trope entirely.
In order to save Athena in Saint Seiya, the main characters must walk through the twelve zodiac houses and confront the Gold Saints whenever it's necessary. Fortunately, Aries won't be a major concern. Mu, the house's guardian, is in the good guys' side, and after jokingly faking a battle with them, he proceeds to repair their (at that point weakened) armors so they can be better prepared. Mu also gives them suggestions about how to confront the remaining Gold Saints.
After being revived in YuYu Hakusho, Yusuke helps Kuwabara get rid of a bully who was threatening him. It turns out that said bully was possessed by a little demon, so when Yusuke grabs it, Botan tells him about it and its crimes, and takes the opportunity to tell him that Koenma hired him to work as a Detective Spirit, making that little demon the first supernatural criminal he captures. Of course, the subsequent ones are a lot harder to defeat.
The Golden Voyage of Sinbad. The Grand Vizier of Marabia gives Sinbad a quest to find the three golden tablets before the evil Koura does. Luckily Sinbad accidentally acquired the first tablet from Koura before meeting the Vizier, and uses it to locate the area where the other two tablets can be found.
The quest for the Horcruxes in Harry Potter is a Double Subversion. The first Horcrux destroyed was Riddle's Diary, four years before Harry even knew it was such. And it took the plot of an entire book (Chamber of Secrets) to destroy it, so it wouldn't fit the trope. However, in Half Blood Prince, when Dumbledore tells Harry about Horcruxes and the importance of destroying them, he tells him that not only the diary is already out of the concerns, so is Marvolo Gaunt's Ring, which he and Snape had already found and gotten rid of prior to the events of Half Blood Prince.
In the second book in The Dark Is Rising series, Will Stanton is given the first Sign, the Sign of Iron, before he even learns that he is an Old One and starts his quest for the other five Signs.
Live Action TV
The Outer Limits TOS episode ''Demon with a Glass Hand". Trent must find the three missing fingers of his artificial left hand to save humanity from the Kyben invasion. Fortunately Trent's incomplete left hand is a computer that can help him find the three fingers.
Banjo-Kazooie has Jigsaw Pieces as Mac Guffins. They are required to complete magical pictures that open the levels they portray. Who tells the title characters about this? The first Jigsaw Piece, of course.
Largely averted in The Legend of Zelda games, where Link has to traverse through a dungeon and other places before gaining the first of the Plot Coupon items. However, there are a few exceptions:
In Ocarina of Time, after Ganondorf takes over Hyrule and Link wakes up from his seven-year slumber, the first Sage tells him that all others have to be awaken so they can together capture and seal Ganondorf. He also gives him the first Sage Medallion, Light.
In Twilight Princess, Link and Midna must reunite the four fragments of the Mirror of Twilight in order to enter Zant's whereabouts. The first fragment, luckily, is still in the Mirror when they find it broken, so they only have to look for three more.
Also in Twilight Princess, Midna is already wearing the first piece of the four Fused Shadows when the player meets her.
In Skyward Sword, the first Ancient Tablet is already given to him by Fi in Skyloft, allowing him to gain access to the first area of the Surface, Faron Woods. The trope is inverted in the Song of the Hero quest, as Levias is the character that tells Link about the song and the parts of it that were taught separately to him and the three Dragons guarding the areas of the Surface, but he won't teach him his part until all others are learned.
In Star Fox Adventures, a character tells Krystal that the Krazoa Spirits are the only beings capable of bringing an end to the war that is wounding the population of planet Sauria. He even tells her that the shrine guarding the first Krazoa Spirit is a few steps on her right side.
Mass Effect 1, Shepard accidentally finds a Prothean beacon in the end of the tutorial level. It proves to be the first in line of Mac Guffins you have to collect before you can beat the Big Bad, namely, the Prothean Cipher that allows to decode the beacon's message, the MacGuffin Girl Liara who does the actual decoding, and the coordinates of the Point of No Return kept by the Rachni Queen.
In ''King's Quest: Mask of Eternity the entire reason why Connor is the hero is because he picked up a piece of the Mask (one of five plot-necessary Mac Guffins) before the spell that turned everyone else to stone could hit. Everyone acts as though he's the destined hero, but if that's true then Destiny must've aimed that mask piece directly at him.
In Super Paper Mario, Mario gets the first Pure Heart handed to him before the player even officially has control of him. Hilariously, you can avert But Thou Must by refusing multiple times to accept the first Plot Coupon, eventually leading to the giver just giving up and a Non-Standard Game Over before the game even begins.
Mario's goal in Super Mario Galaxy is to retrieve the Grand Stars that fuel the Comet Observatory built by Rosalina. Luckily for him, the first of these Stars is the only one that isn't guarded by any of the bosses, in fact its power hasn't been fully used yet. Also a case of Back from the Brink.
Ōkami has a sidequest-based example: In Shinshu field, a pirest asks Amaterasu to hunt down five criminal demons, each marked with a sacred arrow. As soon as the titular wolf exits the priest's house to start the search, night falls and the first criminal demon challenges her to a fight.
Cruelly inverted in Jet Force Gemini: When Mizar escapes from his palace after Lupus easily defeats him, he threatens the characters to redirect an asteroid to blow up planet Earth. Aware of this, King Jeff tells the protagonists that there is a huge mothership that will help them intercept the asteroid and find a way to stop it, but it's missing twelve pieces. Eleven of these pieces are scattered through the galaxy, so the three characters have to do a Fetch Quest to retrieve them. The 12th piece, technically the first, is in Jeff's hands, but he won't give it away until all 282 missing tribals in the game are rescued. He doesn't even care if the aforementioned asteroid manages to hit Earth in the meantime.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.