How do I go to my payment method options?
I get a notice saying payPal is not supported on this device, (iphone5). To manage or change payment method, go to your iTunes store on your computer before you can purchase anything.
Need help!
iPhone 5
On your computer's iTunes you should be able to edit your payment info by going into the Store > View Account menu option and logging into your account, and on your account's details page there should be a payment link.
Changing payment info : http://support.apple.com/kb/HT1918