Fictional Currency

Money is an important part of daily life, and fiction is no different. And fictional setting often use fictional currency.

Inventing a fictional currency helps establish a setting as unique, and when done well it builds immersion. Of course, when done poorly, it can have the opposite effect — having an unexpected or unexplained reference to a made-up word that means "money" can be confusing or distracting. Often, a fictional currency will be roughly equivalent in value to a real-life one; this saves the writer the effort of having to do conversion rates mentally. The most common targets for this treatment tend to be the dollar or the yen. This is occasionally explicit, as with the double dollar or the nuyen. The zeni (or zenny) is a popular name for fictional currencies in Japanese media.

Compare Call a Rabbit a Smeerp, though Justified in that one generally expects there to be different names for different currencies. Contrast Gold-Silver-Copper Standard, where the money used isn't a currency at all, but precious metals are used instead; the two may overlap when different names are given to the appropriate coins. Examples are often a Global Currency. We Will Spend Credits in the Future is a Science Fiction-specific subtrope.

Anime and Manga

 * Trigun uses double dollars (and c-cents are mentioned once); as expected, they're generally equivalent to dollars.
 * Cowboy Bebop uses woolongs, which are roughly equal to yen. Its symbol (₩) is even similar to the yen symbol (¥), with the Y replaced by a W -- ₩ is incidentally also the currency symbol for the North Korean won and South Korean won.
 * Dragon Ball uses zeni.
 * Bleach uses kan, which serves as Soul Society's official currency.
 * One Piece has Berries used throughout the ocean-going world.
 * The sky islands the Straw Hats visit use Extols, which have a 10,000:1 exchange rate with Berries.
 * Fullmetal Alchemist uses cenz.
 * Hunter X Hunter uses jenny.
 * Outlaw Star use wong.
 * Naruto uses ryō, which Word of God states has a 10:1 exchange rate with yen.
 * Fairy Tail uses Jewels.

Comic Books

 * In Groo the Wanderer, kopins seem to be a Global Currency.
 * Bionicle has widgets.

Film

 * The unit of currency in The Sword and the Sorcerer is the Talon. Which coincidentally -- or perhaps not coincidentally -- is also the name of the movie's hero.

Literature

 * New Yen in the Sprawl Trilogy
 * In Harry Potter, wizarding Britain uses galleons, sickles and knuts; overlaps with Gold Silver Bronze Standard.
 * Gor has Tarn Disks/Tarsks, which use the Gold-Silver-Copper Standard.
 * Played with in The Hitchhiker's Guide to the Galaxy. In The Hitchhikers Guide to The Galaxy, a group of people have crash-landed on an uninhabited planet. They decide to adopt the leaf as their currency. The upside: Everyone immediately becomes fantastically rich. The downside: it costs approximately three entire forests to buy one peanut. The solution: burn down all the trees.

The Hitchhiker's Guide to the Galaxy also mentions a few galactic currencies, all of which have fallen into disfavor: The Altairian Dollar (due to inflation), and the Galactic Piu (due to being equal to 8 triangular rubber coins 6000 miles on a side that no one is rich enough to afford).
 * A Song of Ice and Fire has dragons and stags after the Animal Motifs used by the former and current dynasties.
 * The Wheel of Time has three terms for coinage: penny, mark and crown. However, these can be made of different materials, with a gold mark, say, being worth more than a silver crown. All told, because coppers are always pennies and golds never are, there are six different varieties of coin in use, with their exact relative values differing by country of origin.
 * The Stormlight Archive has currency called "spheres", consisting of gemstones encased in glass. Value depends on the type and size of the gem (the spheres themselves are all the same size). The denominations (from lowest to highest) are "chips", "marks", and "broams", with emeralds being the most valuable stone and diamonds the least. Spheres infused with Stormlight (which makes them glow) are also more valuable because it's a guarantee that they're not counterfeit. (Infused spheres also make convenient sources of light.)

Live Action TV

 * In the Star Trek universe, the Klingon Empire's currency is the darsek. The Bajorans use a currency called lita, and the Cardassian Union has the lek. The Karemma, part of the Dominion, use dirak. The Star Trek Novel Verse has added several others, including Tarkaelean notch-rocks, Gorn szeket, and Breen sakto.
 * Naturally, your local Ferengi currency exchanger is more than happy to turn all of this into gold-pressed latinum, in easy-to-handle denominations of slips, strips, bars, and so on. Note that the gold is considered worthless, it's the liquid latinum inside that holds value.
 * Thanks to approved tie-in material, we know the currency for many of the alien nations on Babylon 5: Abbai use gy, nori and chuk, Brakiri use grull or credits, Drazi use tok, Grome use vorl, Hurr use fla, Llort use yat, heek and molat, Markab used galot and Yolu use ogo. Hyach and pak'ma'ra use a barter system instead. The Centauri use ducats and the Humans use credits. No word on the Narn or Minbari.
 * At least three million years in the past of Red Dwarf, humanity used the 'dollarpound' ('buckquid' for short).

Tabletop Games

 * Monopoly money may be the Trope Codifier. In some spinoff games like Monopoly City, it's denominated in "monos" (the symbol is a struck-through M; the name is a riff on Euros). In addition, some versions have used game-oriented names, like the pre-euro German "spielmark".
 * Nuyen (¥) in Shadowrun.

Toys

 * Widgets in Bionicle.

Video Games

 * The Western translations of the Pokémon games use "Poke Dollars"/"Poke Yen", which look like Yen but with a P instead of a Y. The Japanese version just used Yen. Even in the region based on New York.
 * The Final Fantasy franchise uses gil, in one of the most recognizable instances of this trope.
 * The Kingdom Hearts spinoff games use munny instead, however. Strangely enough, instead of coins, it takes the forms of yellow octahedrons.
 * The iPod tactical game Song Summoner: The Unsung Heroes uses Luna
 * The Legend of Zelda franchise similarly uses rupees, which is oddly enough a real currency (used by India), though no one's quite sure if it's supposed to be a reference to that or a pun on the word "rubies", since Zelda's rupees look rather like absurdly large gemstones.
 * The Shin Megami Tensei series, save for the Persona subseries, uses macca. It has some relevance as a power source for demons.
 * Sim City and The Sims both use the simoleon as their currency and the currency sign for it is a section sign (§).
 * Suikoden games' currency is the potch.
 * Nethack has zorkmids.
 * Exit Fate has the arn.
 * Zenny in the Breath of Fire series, as well as most other Capcom games: the symbol is generally a Z with vertical lines through it.
 * Kingdom of Loathing uses meat as currency, while precious metals are Vendor Trash.
 * The Elder Scrolls call their gold coins "Septims" after the imperial dynasty.
 * Phantasy Star uses meseta.
 * Black Tiger, another Capcom game, also uses zenny.
 * Legend of Mana uses "lucre", but not the rest of the World of Mana.
 * Fusion Fall uses taro.
 * Dragon Age uses sovereigns.
 * Tales (series) uses Gald.
 * Star Ocean and its sequels use Fol.
 * Subverted in the Mario RPGs Super Mario RPG, Paper Mario and Mario and Luigi with the Coins. While coins are common in the real world, apparently they are their own currency in Mushroom Kingdom and any adjacent places.
 * Ultima games usually have gold coins, but Ultima VII Part II takes place on another continent, where three city states have different coinage each. Warlike Monitor uses monetari (huge golden coins), beauty-fixated Fawn uses filari (small gems encased in glass), and magical Moonshade uses guilders (enchanted glowing chips). The exchange rates are fixed, but different moneychangers take different fee for exchange.
 * Ultima VIII, which takes place on another world, uses obsidian coins.
 * The Freddi Fish series has purple sea urchins. There are at least five variations, all of which are more valuable: red sea urchins (worth two purple ones), blue sea urchins (worth three purple ones), gold sea urchins (worth four purple ones), and orange sea urchins (worth more than four purple ones; exact value unknown).

Western Animation

 * Chowder has dollops.
 * The currency on Invader Zim -- seemingly both on Earth and in the Irken empire - is "moneys", as in "that costs six moneys."
 * Tripping the Rift has kronigs.
 * Dave the Barbarian has dreckles.
 * Samurai Jack, googleplex is the main currency in the time period ruled by Aku.
 * The Fire Nation in Avatar: The Last Airbender uses a currency called "Bǎn".
 * The Flintstones has clams. Which are usually literal clams.
 * Team Umizoomi has Umi Dollars/Umi Cents.
 * Various incarnations of My Little Pony franchise have had their own currencies:
 * My Little Pony Tales had jangles.
 * My Little Pony Friendship Is Magic has bits.