No, you don’t need a credit card to purchase in-app items or premium games. You can easily purchase premium games or in-app items by tapping the “buy” button, and the charge will go directly on your Sprint mobile bill. If you are a Boost Mobile or Virgin Mobile USA customer, any charges will be automatically be taken out of your account each month.   If you would like to add a credit card, you can go under settings, and press "Add Credit Card Info" where you can put your information. Alternately, you can also use Playcredits to purchase in-app items or premium games.