rAthe uses the payment method that is associated with your Apple ID account to pay for episodes.  In order to use an iPhone, a user is required to have an Apple ID.  To make iTunes or App purchases on the iPhone, a user is required to input their payment method information.  Possible payment methods include credit card, debit card, or Apple Gift Card.  If you want to make an app purchase and do not have a payment method on file, Apple will redirect you to add that information under iPhone settings.