In IRAN, You need to bring enough cash with yourself and convert it into IRANIAN Rial. Visa & Master cards cannot be used here. US dollar and Euro are the most preferred currencies to be changed in exchange offices (Sarafi). The important issue regarding Iran currency is that although Iran Official Currency is Rial, but you will hear Toman more commonly and it may be confusing. Toman is one-tenth of Rial. It will be better to ask about the price although written on the items.
You can check out the most updated IRANIAN Rial rate in www.