[Fluffagrams]

It depends on the kind of card you mean.

I'm not too sure on what the card they sell in stationary shops would be like for use with hamsters and would probably stick to something like plain, cheap toilet tissue myself.

I have given my hamsters cardboard boxes from biscuits, teabags and the like to play with many times and they've been fine with that, even when they've chewed them so that could be an option for you but it depends on what you're hoping to do with it.