When you cross the border, go to a bank and convert US dollars for CA, you should get at least $500CA for expenses such as restaurants, tips, emergencies, etc and have either a MasterCard or Visa. ragftw above has everything nailed down quite well. The exchange rate right now is almaost 20%, $1.00 US equals $1.20 CA, so it's best not to pay with US funds if you can avoid it. However, by nest summer the exchange rate will probably be more favorable and the US and CA dollars might even be at par. Make sure you notify your CC companies of your travel plans so they don't cut you off.