The currency in Peru is the Peruvian Sol (PEN) (plural: Soles). Currently 1 USD is worth approximately 3 PEN and 1 CAD is worth approximately 2.5 PEN (December 2017). You will be able to use USD to purchase in larger establishments, but we do recommend getting some Soles either before your trip or in the airport. Our guide will also show you money exchange places with the best exchange rates throughout the trip.
You will also be able to pay by card in larger establishments, and there are ATM machines in Cuzco, Lima and Puno if you wish to withdraw more money.