What kind of currency are we going to use for the RP, and what is the money standard?

I was thinking dollars, cause it would be easier, but Yen is the Japanese currency.

Also I can be in charge of the stores, and setting all the prices (with advice from whoever gives it).

And finally, how much money (max) does everyone start with? and how do they earn money through the game?

(these don't need to be answered now, but they might be asked later).