Zeni (Ƶ, occasionally spelled "Zenni" or "Zenie") is a type of currency in the Dragon Ball series and dub & Peter 1. According to Akira Toriyama, one Zeni is equivalent to one Yen, which is the real-world Japanese currency.
Zeni is often the prize for winning in a World Martial Arts Tournament. In the FUNimation dub of Dragon Ball Z, there are a few mistakes on the translations of Zeni amounts from Japanese to English: one example is in the episode "A New Friend" at the Taitans game, Yamcha asks for a 20,000 Zeni bonus, however, in the Japanese dub, he asks for Two Million Zeni. Since Ƶ1 equals ¥1, Ƶ2,000,000 was roughly $29,200 in modern dollars, given the exchange rate between yen and USD at the time the episode aired and the inflation between USD then and now (circa 2014). At this rate, Ƶ20,000 is roughly $292. This is likely because American viewers would be familiar with the dollar, which is worth much more than the yen. The currency translation errors in the first season were never fixed in the later FUNimation Remastered Box Sets.
The only other known currency in the series is the Gammets used on Imecka, but in an episode of Dragon Ball there are wanted posters of Launch, the Tori-Bot, and other characters with dollar signs ($) representing their awards suggesting dollars may also exist exclusive to the anime.
Video game appearances
Zeni are featured in many Dragon Ball Z video games, such as Dragon Ball Z: Super Saiya Densetsu, Dragon Ball Z: Shin Butōden, the Legacy of Goku series, the Budokai series, the Budokai Tenkaichi series (called Z Points in Budokai Tenkaichi 3), Dragon Ball Z: Harukanaru Densetsu, Dragon Ball Z: Attack of the Saiyans, Dragon Ball: Revenge of King Piccolo, and Dragon Ball Online. It is also the currency used in the crossover game Famicom Jump: Hero Retsuden.
In the World Tournament in Dragon Ball Z: Budokai, second place wins 5000 Zeni and first place wins 10000 Zeni. In the Budokai Tenkaichi series, Zeni can be found on the story mode of the game and winning a tournament in the World Tournament mode in order to buy techniques, items etc. in the game's shop (alternatively, Zeni can also be earned by finishing runner-up after losing in the final).
In Dragon Ball: Xenoverse, Zeni is the currency used in Toki Toki City. In the game, there are also items called a Hercule Badges which is a coin-shaped medallion with Mr. Satan's face on them. This badges are quite valuable depending on their rarity and can be exchanged at shops for a certain amount Zeni (the more rare the badge the is the more Zeni it is worth) in Toki Toki City's Industrial Sector. There are 5 kinds of Hercule Badge (Common, Uncommon, Rare, Super Rare, and Legendary). Zeni can also be obtained via making a wish to Shenron.