T-Mobile guarantees the best trade-in price on your used mobile devices

T-Mobile today announced the US carrier will be guaranteeing the best trade-in prices for customers. The company aims to best AT&T, Sprint and Verizon by offering $50, as well as the difference back, if consumers find a better deal elsewhere. It's for a limited time only and kicks off on September 17. T-Mobile will monitor the market and adjust trade-in prices accordingly.

source: androidcentral