The Iranian currency is now officially called Tomans instead of the Rial. The denominations in use are 100, 200, 500,1000,2000,5000,10000,50000 and 100000 Tomans ( as they are referred to by the locals although they all still have the extra zero from the Rial days!). You are unlikely to encounter any of the 100 and 200 toman notes, they are worth very little. Each Euro these days gets you 4000 Tomans (previously 40000 Rials). The banks are NOT the place to exchange as they will buy the hard currency at the governmental rate which is some 30% lower than the free market rate. You get the best rates in bureau de change which you find in most city centers and at major airports. You can sell back your excess Tomans at the end of your trip. For foreign travellers, Iran is still a cash economy. Those who wish not to carry too much cash can take a day off and by taking their Iranian money into a bank ask for a debit card.