Ok for this day I got a gift card, My computer was down but not my phone so I bought quite a few apps. When I went to Itunes I saw that my gift card was untouched so I looked if it was charging the debit/credit card link to my account nothing was on it. So I am wondering if it put them on the phone bill?
It takes from the method on your Apple account. If the card isn't listed as a method of payment it's going to take whatever method you have selected.