…here’s your answer, straight from the playstation site:

You can use the following forms of payment to purchase items at the PLAYSTATION®Store:

* MasterCard
* Visa
* Discover
* American Express
* Debit and check cards with the official MasterCard or Visa logos printed on them
* PLAYSTATION®Network Card (PSN Card
The PLAYSTATION®Network Card (PSN Card) is a prepaid card that may be used to apply funds to a PLAYSTATION®Wallet without using a credit card. Please visit your local authorized PlayStation® retailer to purchase the PSN Card. The PSN Card is only available for use on PLAYSTATION®Network Master Accounts with a United States address. Please note that we do not recommend using prepaid cards other than the PLAYSTATION Network Card, as they may not be accepted by the PLAYSTATION Network.

Notes:

* Verify with your bank whether your credit or debit card is compatible with Address Verification System (AVS).
* All credit/debit cards for use with the North American PLAYSTATION®3 computer entertainment system, must have a billing address within North America.
* If you are located outside of the North American region, you may still be able to create a PLAYSTATION®Network account using a US or US territory address and purchase content from the North American PLAYSTATION Store, however, you must have a North American credit card or debit card (with a Visa or MasterCard logo).
* If you have issues entering billing information onto your PLAYSTATION Network account, please see our guidelines for entering billing information.

Buy Prepaid cards at stores such as Walmart, Walgreens, Right-Aid, etc.

Prepaid cards normaly dont work on things on the internet. You just use them at stores or whatever. Just ask your mom for her credit card. Tell her you’ll do some chores around the house. Works for me…

try real money,,,,,

Try it again later or with a different credit card, sometimes that’s a temporary glitch. Or you can wait another month or so until we get the network cards. I know, sucks that we don’t have em yet, huh?