T-Mobile will match device trade-in prices to attract new iPhone customers

When a new iPhone is announced, carriers see it as an opportunity to gain new subscribers. T-Mobile’s gambit for new iPhone customers this cycle? It will match and beat used device trade-in offers from any of the other big carriers.

The deal works like this: For any device — not just an iPhone — you can figure out your device trade-in value here. If a trade-in offer from [company]Verizon[/company], [company]AT&T[/company] or [company]Sprint[/company] beats the [company]T-Mobile[/company] value within seven days, then you get the difference refunded, as well as a $50 credit that applies to a future T-Mobile bill.

Although T-Mobile offers competitive trade-in prices, you can probably find a better deal from other buyers. For instance, earlier this morning, T-Mobile offered me $150 for my 32GB iPhone 5, but Best Buy beat that with $225. Unfortunately, T-Mobile will not match offers from companies like Gazelle or Best Buy, only carriers. But for those who know they want to switch to T-Mobile, it’s a convenient promotion.

The offer starts on September 17, which should be two days before the latest iPhones go on sale based on previous release schedules. So although this offer applies to all “used devices,” it’s clearly targeted toward the upcoming iPhone. T-Mobile hasn’t been shy in the past about using Apple’s phone to sell plans: Since T-Mobile became an iPhone carrier last year, it has loaned prospective customers an iPhone 5C to “try out” the T-Mobile network, cut $100 off the price of the new-at-the-time iPhone 5 and and even waived down payments on a new iPhone when an older device was traded-in.

T-Mobile is planning an announcement event in San Francisco on September 10.