Currency of Iran is Rial that among people Tooman is so more comfortable than Rial.
If you remove one zero of Rial, it is Tooman. People in Iran you just Rial in banque and in their trades.
If you want to buy somethings from different shops you can use both of them, because shopkeepers understood
that most of tourists are going to be a little confused. But be careful that somebody do not want to ask you more
money in this way.