Peso (ARS; symbol AR$) = 100 centavos. Peso notes are in denominations of AR$100, 50, 20, 10, 5 and 2. Coins are in denominations of AR$5, 2 and 1, and in 50, 25, 10, 5 and 1 centavos.
US Dollars are accepted in some hotels and tourist centres. Prices in US Dollars are typically marked with US$ to avoid confusion, but sometimes both peso and dollar prices are both preceded by just $, so check if unsure.