How much is One Piece's currency worth? There are many transliterations of the currency: Berry, Beli, Berri.  Which one is the official one?

The Navy just give large bounties for pirates, Buggy has a 15 million bounty and Luffy has a 30 million.  Would Luffy's bounty be an equivalent to 30 million Yen? 

What would be the real world value of the currency used in One Piece?
In the original, it's called Beli in English. However, if the Japanese word is translated correctly, it's Beri - it's a feature of the Japanese language (look at SingerOfTheFalls answer). However, it differs in different languages: for example in Germany, it's Berry.

To compare the prices:


One cabbage loaf: 150 Beli
A Bon Chari: 500 Beli for renting, 10,000 Beli for buying
A Doskoi Panda brand shirt: 10,000 Beli
Nami's Jacket: 28,800 Beli




Regarding Luffy's bounty would be an equivalent to 30 million Yen,


   30 million Beli on Luffy's head is a little bit old; his current bounty is 400 million Beli.


Quote:


   Fourth Bounty: Defeating yet another Shichibukai (Gekko Moriah), attacking a World Noble, causing an unprecedented breakout from Impel Down, participating in the Whitebeard War, and by intruding Marine Headquarters a second time and ringing the Ox Bell 16 times (which was taken as a declaration of war), Luffy's bounty has gone up 100,000,000 more to make a total of  400,000,000 making it the third highest active bounty known. The public revelation of his relation to Monkey D. Dragon may also have influenced it.