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.

Social and Class Wealth
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. Rare Adam Wood in contrast, being sold on the Black Market reaches in price of about 200,000,000.

Bellemere was noted to be too poor to give her daughters everything they needed in life, and when Arlong invaded had only a lifes savings totaling at the time just 100,000 and had proir to this often been on a diet of just oranges to pay for the life she had to offer her daughters. She was the only one in her village unable to pay the full amount Arlong requested at the time of his arrival (100,000 per adult, 50,000 per child) and Arlong continued to demand this amount reglaurly from the villagers of Cocoyashi Village resulting in years of struggle to pay the amount to avoid anyone being killed by Arlong. Arlong had agreed with Nami that she had only to bring 2,000,000 to buy her village back off him, an amount she took 8 years to amass and almost achieved in reaching the goal simply by robbing pirates.

Notably also, Nami once demanded 100,000,000 from Igaram to protect his countries princess, but later it was noted that the country did not even have this amount of wealth to offer as it was on the verge of civil war. The Straw Hats considered themselves "wealthy" after gaining gold worth in value 300,000,000. When they lost 200,000,000 of it to the Franky Family they noted their remaining 100,000,000 was still enough to buy a decent 2nd hand ship to continue their journey, even though their original full would have bought them a brand new ship of much better quality. The most affordable slaves are humans at 500,000 while 70,000,000 for a female unsplit mermaid is the highest starting bid for any race. Such as, all kidnapping groups seek them out and they present the most profitable auctions, and the storyline hints they can run well into the 100,000,000s, being noted only to be bought by only the wealthest of the One Piece world inhabitants.

However, to a World Noble, a bid of 500,000,000 seems to be a insignificant amount of money to them judging by the way Saint Charloss bidded in the Human Auctioning House. And most note worthy, he bidded this amount off the mark and no one else could counter his bid in the auction house ending the sale of Keimi there and then. His father merely noting his 'waste of money', indicating they have even more wealth then this and while this amount is still considered a waste, means they do not go fear the same scale of finical concerns as the rest of the world. Also, while the limit of bounties is unknown, the maxium Oda noted with have been Enel, had he been a pirate he would have a bounty of 500,000,000 with a note from Oda that there are even strong in the Blue Seas. However the fact the officals would consider offering this amount also indicates that the treasurey for holding bounty rewards has an considerable amount of money to offer or are at least willing to offer and part with that high amount.

So it would seem the difference between the amount of money the richest and poorest of the One Piece world citizens; the poorest families can have less then 100,000 life savings while the richest have a staggering 500,000,000+.

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.
 * 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.