Pay-by-phone lets you make purchases by charging them directly to your monthly...
https://web-wiki.win/index.php/What_Should_I_Tell_Customers_About_Carrier_Billing_and_Privacy%3F
Pay-by-phone lets you make purchases by charging them directly to your monthly phone bill or using prepaid credit. It’s a simple way to buy digital goods without a credit card, making checkout easier on your phone