I agree with Carol. Many restaurants, especially more upscale ones, and most large grocery stores and many shops accept credit cards, especially for larger purchases. But cash is more prevalent than in Canada. So yes, you need to bring some cash, but make sure it is USD, not Canadian! There are ATMs readily available that will dispense USD using your Canadian debit card if you need to replenish the cash, so no need to bring a large stash with you initially.