Why do I get the message "Your payment method was declined" when I try to make an iTunes purchase?

This message means that the issuer of the credit or debit card you have on file in your iTunes account rejected a charge or account confirmation. It is not an Apple problem; Apple is just passing through the message from your issuer. You many need to contact the issuer to find out why the charge was rejected. You can do some self-troubleshooting first, however. Here are the most common reasons a charge might be rejected:

1. Insufficient balance or account in arrears
2. Account suspended for suspected fraud (not necessarily by you)
3. Error in card number
4. Wrong expiration date
5. Wrong CCV code
6. Address in your iTunes account does not match exactly the billing address for the card
7. The card was not issued in the country of the iTunes store