Peru's official currency is the nuevos sol, which consists of 100 centavos. Paper notes range in value from 10 to 200 soles, and coins are minted in amounts of 5, 10, 20 and 50 centavos. Try to keep plenty change and small bills in your wallet; Frommer's explains that breaking large notes is difficult for Peruvian businesses and may cause delays.
American bank notes are accepted throughout Peru, making the U.S. dollar the country's de facto second currency. Many businesses frequented by travelers, including hotels and transport companies, accept only U.S. dollars, so it's wise to bring some American money on your trip.
Counterfeit notes are common in Peru, so always hold bills up to a light source and look for a watermark to ensure their authenticity. ATMs are found throughout the country, and offer some of the best exchange rates, though they may not accept all types of debit and credit cards.