US & Canadian dollars are accepted virtually everywhere, actually preferred over the Cuban Peso. People will offer you a much better exchange rate than the banks (around 25% premium) selling Pesos. One thing to be aware of is that coins are not useful to them (the banks wont accept anything but paper bills). Bring $1 US bills for tips and they will love you. We brought 400 for tips and we were treated like royalty. I wouldn't buy any pesos, completely unnecessary.