Rial is the Iranian currency, but in daily life and for simple purchases, people use another currency named Toman. One Toman equals 10 Rials. In malls, grocery stores and other shops the prices on the goods are written in Rials but if you ask the seller, they will tell you the price in Tomans ( a tenth of the number shown on the price tag) that may cause confusion especially for the tourists. “Is this the currency with the extra zero or not?!” is a question usually asked by the tourists in Iran.
Recently, in December 2016, Iran's government has decided to omit the extra zero and change Iranian currency to Toman, which is more popular among the people. This plan is now under study by the economists and it will probably be approved.
As a result, the financial affairs are going to be done more easily and the tourists won’t be confused while purchasing, calculating and counting their cash in Iran. Check out the article about Iranian currency for more information about carrying money in Iran.