I haven't kept any open long enough to find out for certain, but I've been wondering - since most pre-paid credit cards charge you a monthly fee on the card, what happens when you use up the balance on the card so it's at zero, and just stop using it? Do they continue to charge you another $5 or so monthly fee, sending your balance further and further into a negative balance? And if so, will they expect you to pay that negative balance or do they just close the card if it's not paid within a certain amount of time? I just started buying some of these a few months ago, to take advantage of some trial offers. All but one of them I cancelled as soon as I was done using them. The one card, however, did go like one day past the date where it would implement the $5 fee, and I noticed it was now at a negative balance. I hurried up and cancelled the card online, and it didn't give me any problems. So far I haven't heard anything from them either.