or gmail account
That one used to work, I guess they started banning it once the invite only period ended.
Do you have an e-mail address with your ISP? Someone please correct me if I'm wrong but I think the non-free e-mail is only needed for the credit card payment (i.e. you can change it in your profile afterwards). I seem to recall someone changing its e-mail to gmail afterwards (I would need to check if I can find back the notification for that) but it might have been before they removed gmail.
A lot of mac users have used mac.com and it seems to go through and it looks like you can get 1 free month (would still need to make sure you can change your profile to gmail.com though...) without a CC so that might be an option.
The other solution would be to go through Paypal.