Belly

Beli (ベリー, Berī; represented by the Beli sign: is the unit of monetary currency in One Piece, almost exclusively depicted in paper form, although coins do exist. Although closely resembling United States dollar bills, the large values on the notes harken to the Japanese yen. The beli has no fractional unit.

In the SBS of Volume 53, Oda showed the designs on the coins and notes of One Piece.

Other Currencies
Although the Beli is an universal currncy used nearly worldwide, some isolated countries have own currencies. As of now, two such currencies were mentioned:
 * The Skypeian Extol (エクストル, Ekusutoru) is the currency used in Skypiea. Normally written as a capital "E" with a slash through it like a dollar sign. Ther Extol seems to be pegged to the beli, there are 10,000 Extols per Beli. Nothing else is known about Extol.
 * Gor is used on Amazon Lily. Same for Extol, nothing else is known.

Gallery
 File:Berry banknotes.png|The money in cash form File:100 Berry.png|The money in coins File:Rio-Berry.jpg|The money as represented in the Boss Luffy specials 

Translation and Dub Issues
It should be noted that because of the phonology, multiple English spellings exist; the most common among fans is "Beli", although "Beri" is also used. "Berri" and "Belly" are used too but are somewhat uncommon. "Berry" for singular and "Berries" for plural are used in the English versions. The author has spelled it both as "Berry" and "Belly" on the actual bills.

Trivia

 * Nami's eyes tend to take the shape of the symbol of Beli when she hears that a large amount of money is involved. Especially when explaining that what she is doing has nothing to do with the money.
 * When Oda discussed the Doskoi Panda brand, he mentioned that the line was very expensive. With this is mind, to proper put the currencys value in a real world context, a 10,000 shirt is expensive to the people of the One Piece world.
 * To a World Noble, a bid of 500,000,000 seems to be a insignificant amount of money to them judging by the way Carlos bidded in the Human Auction house. And most note worthy, he bidded this amount off the mark and no one else could counter his bid in the auction house.  Considering there were men of all social ranks present, including royalty, this can be used to signify the difference between the amount of money the richest and poorest of the One Piece worlds hold.
 * In appearance and denomination, the Beli closely resembles the Japanese Yen (日本円 Nihon En). The characters Yukichi Skull, Ichiro Kumaguchi and Hideo Usaguchi portrayed on the beli banknotes are a pun on Hideyo Noguchi, Ichiyō Higuchi and Fukuzawa Yukichi portrayed on the corresponding yen banknotes.
 * In the Boss Luffy specials the currency Rio-beli is used. This currency has no banknotes, only coins and mirrors the Tokugawa coinage that was used in Japan in the Edo period.