Don't worry Crono, you'll be able to afford that someday.
The heroes have arrived at the next town and, in standard Role-Playing Game fashion, head over to the weapon and item shop to upgrade all their gear. They count out some gold to spend, check out some Absurdly Sharp Blades, and get ready to make their purchase.
Only to find that the item is being sold for... A Million Gold?
Teaser equipment occurs when a store is selling powerful and expensive weapons, armor, accessories, or other items for a price far more than the player is expected to have at that point in the game. This is primarily a RPG trope, though other games can also qualify. An instance of teaser equipment generally means one of two things - either you will return later to the town (with more levels, gold, and more powerful gear), or the gear will become more reasonably priced after you've advanced in the plot or undertaken a side-quest to lower the shop prices.
Teaser equipment is incompatible with Sequence Breaking - if you come across equipment far beyond your ability to purchase because you've gone outside the plot, it is not an example of this trope. A subtrope of Game Breaker if you are actually able to purchase the item in question, either through frugality or farming gold; may also be a Disc One Nuke if acquired early enough. Related also to Adam Smith Hates Your Guts, the difference being that whereas the price of the equipment doesn't increase over time, it starts off prohibitively high and your wealth increases to compensate. Compare with Level Locked Loot - instead of Character Levels prohibiting your ability to use certain items, insufficient gold blocks access; these two are not mutually exclusive. Almost never the Infinity+1 Sword, though particularly triumphant examples may be the Infinity–1 Sword.
Don't confuse with A Taste of Power - that trope is when you get to use really high powered gear early in the game, only to have it taken away from you, while this one taunts you with said gear in the item shop, but you don't get to acquire it until later. A specific type of inversion of the Sorting Algorithm of Weapon Effectiveness.
Chrono Trigger - The first time you arrive at Medina, the shopkeepers sell weapons three tiers above what you'll currently be using, for 10 times the gold you'd expect. Justified in that the fiends of the village hate humans after losing a war 400 years ago. After you've changed history to make fiends no longer hate humans, the prices become more reasonable, but by then, the gear is outclassed.
Another example occurs at the very beginning of the game. The Guru Melchior is visiting the Millennial Fair and has a Silver Sword for sale. Unless you farm money for a long time, you won't be able to afford it until you've progressed through at least one more dungeon.
In the first Diablo game, the enterprising young boy Wirt randomly sells a high-level item, but you're unlikely to be able to purchase it until later. Even though that item is generated at random, it's generally of a higher level than what the normal item shops are selling, though not always relevant to your class. By the time you'll generally be able to purchase it, the gear in other shops has largely caught up.
Dragon Age: Origins features Blood Dragon Armor. Although you receive the breastplate for free early on, you must purchase the rest of the set for massive amounts of money. Even if you could afford it, you still wouldn't be able to equip it until you gain more levels.
The town of Imperia in Gladius displays high-level equipment meant for when you challenge the endgame tournament. Depending on which character you choose, it will either be the first or second region you visit.
Alternate clothing can be purchased from the police station early on in Persona 3. By the time you'll be able to afford it, more effective armor is already available.
Inverted in all the main series Pokémon games. Even if you have the money to do so, shops refuse to sell you the higher level Poke Balls and healing items until you've advanced the plot and obtained sufficient Gym Badges.
Star Ocean: Till the End of Time - When you first arrive in Airyglyph City, several powerful weapons and items are sold for 20,000 Fol or more when you'll have barely a tenth of that. Purchasing this gear early is a godsend on the higher difficulties.
Tales of the Abyss has a variation: shops will regularly display items they do not sell at all until you partake in sidequests (the same sidequests also reduce the prices of items that you can buy.) Some shopkeepers will even have their entire stock "Sold Out" until you do the necessary sidequests, yet they will still thank you for "shopping" at their outlets.
Betrayal at Krondor: The shops in the first area of the game sell some really nifty swords, armor, and crossbows, usually for around 700-800 gold a pop...at a time where you're lucky to have more than 50 or so (unless you spend an inordinate amount of time grinding).
In Phantasy Star III, the two Layan cities at the end of the first generation (and the very start of the second generation, if you decided to marry Maia) sell not only some of the game's strongest equipment, but also a handful of extremely powerful healing items that are not sold anywhere else. While the equipment's prices tend to keep it well out of your range, it's possible to grind enough money (much easier at the start of Ayn's path) to afford some of the healing items, which, if given to Wren and/or Mieu and held on to, can make some of the final battles much easier.
Seltzer in Star Ocean: The Second Story is sold at many shops throughout the game, starts out prohibitively expensive, and its price continues to rise dramatically based on the total playing time. Unlike most examples, this is just a somewhat useful out-of-battle healing item, so there's not even much reason to buy one anyhow.
Alundra has two separate examples of this. The first is the Inoa shop, which always has the Silver Armor in stock, but picking it up will have the shopkeeper tell you it's not for sale. You won't be able to acquire this until the very end of the game. The second example is somewhat similar to the Pokemon bicycle mentioned above. About 1/3 of the way through the game, a shop will open on the beach, which sells Life Vessels and several unique accessories for 10,000 Gilder, exactly one more than the max of 9,999. A subquest a bit later on allows you to obtain these in exchange for the Gilded Falcons you find here and there throughout the game.
The Fallout series occasionally has equipment sold by NPCs that maybe be just out of your price range, moreso when you've just started and lack any caps. The Gun Runner's Arsenal for New Vegas can fall into this trope heavily, as it distributes the new weapons and weapon mods throughout the game in the inventories of most vendors quite randomly, so you might wind up looking through an early-game NPC's stock to find items that you wouldn't be able to afford without procuring a downright absurd amount of loot.
Knights of the Old Republic has a couple merchants on Dantooine with some shockingly good gear at just as shockingly high prices. The Rodian merchant outside the Jedi enclave, for example, sells one of the best heavy armors in game (Cassus Fett's armor). If you want it, you have to get very good at Pazaak, do a lot of griniding, or make a return trip before you get the third Star Map because Malak's attack on Dantooine means the merchants and their items are Lost Forever
In the second game in The Denpa Men series, there's a shop that's only available before setting foot inside the Noob Cave that sells a number of rare and expensive items, including one that increases the rare item drop rate. It's normally only available as an ultra rare drop from one of the mushroom enemies in the overworld. If you don't buy it then (for 20k gold—when most enemies drop single-digit amounts), the only way to get it is either to hope it Randomly Drops or to wait for a certain shop to open up in the endgame.
Link's Awakening features the Shovel (200 rupees), and later the Bow (980 rupees) in the item shop, long before you are expected to be able to afford them. Granted, you can cheap out the Crane Game in order to buy both items right at the beginning of the game (or just steal them)...
Twilight Princess - The shop at Castle Town sells bombs, arrows, and other mundane items for thousands of rupees - the exact same gear can be bought elsewhere for 1% of the cost, or found on monsters roaming town, with the exception of a unique set of Magic Armor that costs a hundred thousand. The absolute maximum number of rupees Link can carry at all is 1,000. Once you give enough money to Malo (which doesn't even come close to the amount needed to buy one pack of bombs from the Castle Town shop — go figure), he buys out the shop, which reduces the cost of items immensely.
Happens a lot near the beginning of Ocarina of Time, where some shops have items whose price exceeds what you can even store in your wallet.
Referenced in Homestuck, after one of the characters earns a large sum of "grist" for leveling up:
"You can't wait to find out what amazing items this new supply of grist will be just barely insufficient to produce."
Real Life also plays this straight with expensive cars, houses, jewelry, and other big-ticket items. Fortunately, a lot of this stuff falls into Bragging Rights Reward.
In Faxanadu, one of the game's most powerful spells can be bought near the beginning...if you have obscene amounts of gold. You can either grind for a very long time, or get the spell near the end of the game.