As of right now, Google's mobile payment tech only works on Sprint phones with Citi Bank Master Cards. That applies to a very specific set of people. Of course, Google doesn't have the only digital wallet replacement out there. For everyone else, there's Verizon, who has teamed up with T-Mobile and At&T to work on its version, Isis, which will begin trials next year, note Efrati and Troianovski. And Visa too is apparently in the works for its own mobile payments system, they add. We also can't forget third party apps like Square, Venmo and ZipPay, which allow users to pay others who have the app using stored credit card information. This almost works as a replacement for the wallet, and would theoretically work better than Google Wallet, if only every single place everywhere accepted Square payments -- but they don't.