No ATMs for foreign cards thanks to sanctions, so you need to bring all your money in cash. Dollars and Euros are recommended. The official currency unit is Iranian Rials, but people use Tomans as the common currency unit. 1 Toman is 10 Rials. For calculating the prices in Rials, all you need to do is adding a 0 to the price in Toman. It would be so helpful if you learn the numbers in Persian.