To purchase items from AppStore or Google Play without using credit cards - you can buy gift cards. These are for sale on Electronic stores.
Apple: http://store.apple.com/nz/personalize/itunes?product=ITUNES_GIFT_CARDS-101703
Android: https://play.google.com/intl/en-US_us/about/giftcards/
Hope this helps.
Jazkallah Khair for using our application.