In Japan, there's a money hand gesture that's very similar to the "OK" hand gesture in America: it's done by making a circle with the thumb and index finger.
Anime: Nisemonogatari 偽物語 (Episode 1)
- haa? kono yo ni okane igai nani ka aru-n-desu ka?
はぁ?この世にお金以外なにかあるんですか?
Hah? In this world, is there anything besides money?
This gesture is used not only to talk about hard cash, but also when talking about profits or other economic gains, about costs, things that are expensive, and so on. It just signifies money in general.
Warning: different cultures use the same gesture to signify different things. In Japan it's money, in America it's "OK," in some countries it's something obscene, and so on. Some culture also have different gestures for money, like rubbing the index and thumb together.