Local money is the tugrik. It’s composed of 1, 5, 10, 20, 50, 100, 500 1.000, 5.000, 10.000 and 20.000-tugriks banknotes. The face of Genghis Khan or Sukhbaatar is represented on each banknote. The exchange rate constantly varies. On the 1st of January 2015, 1 euro was 2150 MNT, 1 dollar was 1876 MNT, and one pound was 2920 MNT. You don't need to change euros in US dollars before coming to Mongolia, euros can be changed directly in Ulan Bator.
Except Ulan Bator and a few other big cities, it's not possible to use your internation credit card or to withdraw money. You're adviced to have tugriks with you as soon as you'll go far from the capital. The Visa card is accepted in more places than Master Card (that is accepted only by the Golomt Bank, Ulan Bator). You don't need to change money at the airport or the hotel, your guide will come with you to the exchange offices whose commissions are more attractive.
Although Mongolia has a very low standard of living, it remains rather expensive regarding electronic goods, household equipment or farmproduce products. In effects, the country has a very low level of production and is very dependent from the imports. For your stay in Mongolia, you’re recommended to bring between 50 and 100 euros per person for your personal consumptions. In Ulan Bator, a meal in a good restaurant costs about 10 euros and a beer (0,5 liter) costs between 1 and 1,50 euro (1,13-1,70 USD ; 0,74-1,12 GBP). Cashmere is a solid value. A pullover costs about 50 euros (56,71 USD ; 36,22 GBP), and a scarf 20 euros (22,67 USD ; 14,88 GBP).