Soon you may be able to purchase a new pair of jeans online, and pay for them on your monthly phone bill. T-Mobile is now opening up its carrier-billing system to online retailers, who can opt to allow customers to pay for their purchases online essentially with their phone- paying for those purchases come the end of the month when their phone bill arrives. Verizon recently announced a similar agreement with American Express.

Transactions made with T-Mobile‘s payment option are designed to be used for music and games, with a cap of $25 per transaction and $200 each month.

T-Mobile will “initially utilize billing services provided by BilltoMobile, Boku, OpenMarket, Payfone, and Zong, simplifies the browse-to-purchase experience for consumers, eliminating the need to manually enter credit card information.” The service is expected to be available later this month.

I’m pretty curious to hear what you all think of mobile purchasing like this. Could you see yourself making purchases online and having them added to your phone bill, or would you prefer to use traditional credit cards to make purchases?

For me, the cap of $25 per transaction and $200 per month is what sells this service. Making purchases online isn’t going to destroy my monthly phone bill, and billing things like a $.99 song download or a game I want to my phone bill is a lot easier than pulling out a card to make a purchase on the go.

What do you think?