The currency of Bulgaria is the Lev - or in the plural form - Leva (In Bulgarian, "lev" is the old word for lion). The coins are called "stotinka" or "stotinki" (in plural).
The exchange rate to euro is: 1 EUR = 1.95583 BGN (~2 BGN).
Notes are in denominations of 100, 50, 20, 10, 5, 2 and 1.
Coins are in denominations of 1 lev and 50, 20, 10, 5, 2 and 1 stotinki . You can exchange money at banks, at large hotels and at independent currency exchange offices, where the rates are clearly displayed.
Debit/credit cards from the types American Express, Diners Club, MasterCard and Visa are accepted in large cities, in larger hotels and car hire offices, and in some restaurants and shops, mainly in the big cities. However, Bulgaria is still a country that operates mainly on cash. ATMs are widespread, although it is best to check with the relevant bank/card provider prior to travel.