What did the Inca use for a currency?

They didn't have one. They didn't understand money, but they traded things. Gold was their favorite metal because of it's color. They worshiped the sun and they thought it was a god.

They did have one thing they used as money. Woman would trade cloths (like money) for other luxury items such as gold and jewels or clothing. Trading with cloth mostly happened among woman of the Inca.