It's a Visa 'Check Card'. My bank doesn't even charge a fee, as long as I use it at least 5 times a month (never a problem). It comes out of my checking account instantly, so the money has to actually be there and there's no actual 'credit'. (Although many places offer the choice of whether to make it a debit (with your pin number) or credit and it works either way.)

I've never had any trouble buying stuff online. The only thing you aren't supposed to be able to do is one of those split payment deals, like where it would charge a certain amount each month.. I think they must know by the numbers whether it's an actual credit card in cases like that.

Visa. It's everywhere you want to be.

Edit: I'd avoid MasterCard if possible. Fewer places seem to take it and even Wal Marts here recently stopped accepting them for credit (still can be used as debit) because they apparently charge the stores higher fees for processing.