You can use the Debit/Credit card feature I think so long as you're a Verified user. They just give you a credit card number and expiration date, and you use that when filling it billing information - which is pretty frikkin' cool!
The downside to this thing though is that your limit is $150 a day I think. So, you can't buy a computer with the money in there, and I had trouble buying some RAM back in the day when I used it... so as long as you're only buying below $150, the feature is great