Celtic Heroes

Bare with me here. Please just read this all so you may be able to FULLY understand. Ok so heres the deal.. My girlfriends parents got her a new iphone 4s and she gave me her old iphone 4. I WANT TO BUY PLATINUM!!!!
BUT, I have been using her apple ID and stuff. Her ID is supported by her parents credit or debit apple. I have a prepaid apple with my own money on it.... I dont want to charge her parents and then have them freak out or something. Is there any way i can enter my own apple number in somewhere that way im buying my own platinum. I do not have an apple ID by the way if that helps. Also let me know if you COMPLETELY understand what I'm saying. Thanks you!!

Prepaid apples dont work with apple sadly, they used to but people were able to exploit the system by going over the apple max so they are no longer supported. Best you can do is use that apple to buy an iTunes apple in a store and use that by entering the code in the App Store and buying plat using existing credit.

Ok thank you! I may just try that!

Ok also, how do you know that......"X" amount of credits is equal to how much U.S. dollars? (When buying platinum). AND how do i add credits to this phone. Obe more thing, Will this FOR SURE work if done correctly? Meaning..., can you spend "Apple Credits" to buy "Platinum"???

You just enter the code and you are credited with apple money, one apple dollar on the account is one US dollar

Just a bit of advice if you are planing to buy x large amount on plat always buy extra $5 $10 on iTunes apples. Because itunes uses the store credit first and any extra charge goes to cc on file ( taxes) .