Wal-Mart Stores plans to sell the T-Mobile G1, powered by Google, for $30 less than T-Mobile, the exclusive U.S. carrier for the device. Wal-Mart said it would start selling the touch screen phone for $148.88 on Wednesday October 29 in about 550 stores for consumers who sign up for a two-year T-Mobile contract. T-Mobile, the No. 4 U.S. mobile service, last week kicked off sales of the device for $179. Wal-Mart spokeswoman Melissa O'Brien said the company wanted to offer its customers the "produc...