Don't they only renew once a year? I wouldn't know, I just buy those prepaid cards when I want to use Live Gold, otherwise the free silver is good enough for me. I love prepaid cards, I f*cking HATE giving my credit card # to companies.
Maybe it's different in the U.S. or Microsoft was just forced to change their policy recently.
I bought a prepaid card/kit, but although it said nothing of the sort anywhere on the box, Microsoft wouldn't activate my account unless I provided a credit card number that gets automatically billed if I don't wait on hold for 6 hours (literally) to request that it not be renewed. But I wasn't allowed to have my account set to not renew until the last minute(
I originally asked for it not to be when I set my first account up).
Many different events have happened with my few attempts to halt renewals. In the end I wound up with two active Gamer Tags.