Canada has always been way ahead of the USA in terms of banking technology, though I suppose the usa has probably finally caught up.

Debit cards will be fine, everything in Canada will be on Interac, and a few other international banking systems, so they can access your account.

You can bring American cash with you and exchange it canada (there is always a place in airports or train stations, if you are taking that).

Frankly, I'd think the tattoo artist would be thrilled to take American cash, but they'd probably ding you on the exchange rate.