This may have been posted before, but its official, PSN cards are now in stores in north america (im in canada, but the U.S will obviously have them), at blockbuster, i was going to pick one up.. But i already use my CC on PSN, All i saw we're 20$ PSN cards, i asked when they got them, they said they had them for the first time on september 15th.
So, if you don't have a CC you don't have to worry anymore :)