If you're a US citizen, you don't need a Visa to get into Canada. They're perfectly happy with Mastercard, Amex, or even cash. :lol:To get into another country you need proof of citizenship and a visa (even for Canada, they give you one at the border for most people)
But seriously, most Canadian border officers would look at you rather strangely if you handed them a US Passport and asked for a stamp in the passport, much less a Visa. And for those crossing with an Enhanced Drivers License or a Passport card, neither a stamp nor a Visa is a possibility.