Hi Ginae790!
I have an article for you that talks a little about the purchasing order of items through the iTunes Store. That article can be found right here:
iTunes Store: How iTunes Store purchases are billed
http://support.apple.com/kb/HT5582
It may still ask you for information from your card on file if that information has lapsed or needs updating. The card information on file has to be correct, no matter what purchasing option you will be exercising for this purchase. Take care, and thanks for visiting the Apple Support Communities.
-Braden