Mobile Operator Billing WoW !!!! You don't need a credit card to buy apps and in-app products in Windows Store and Google Play, because you can use your mobile phone prepaid or postpaid.(Carrier Billing) https://www.windowsphone.com/…/payment-methods-for-the-wind… https://msdn.microsoft.com/…/lib…/windows/apps/mt148540.aspx http://www.windowscentral.com/tag/carrier-billing http://microsoft-news.com/microsoft-announces-carrier-bill…/