Algeria uses the Algerian dinar DZD.
As of April 24, 2015, USD1 = DZD98.
There are 5, 10, 20, 50, 100 and 200 dinar coins. Banknotes circulate in denominations of DZD100, DZD200, DZD500, DZD1000 and DZD2000.
Money can be exchanged at Banks or Post offices. Make sure that the exchanged bills are in a good condition, people tend to be picky with accepting ripped and older bills. Be careful with other currencies than euro or US dollars it could be hard to find a bank that exchange less common currencies.
ATMs are widely available and can be found in every post office or larger bank you can withdraw Algerian dinar with any major credit card and maestro cards. If a pin with 6 numbers is necessary just enter two zeros before your pin.
Living in Algeria is very cheap compared to western conditions. For example, DZD300 will get you a full meal or bus ride from Algiers to Oran 400km. Renting a mid-sized apartment will cost normally DZD60,000 6 months in the advance a month.