Since the merger, you can trade in your Sprint-locked through T-Mobile's Trade-In Program .

While Sprint has officially merged with T-Mobile, trade-in programs for the Go to product viewer dialog for this item.

To ensure you receive the full estimated value, you must meet these criteria: Cell Phone Trade-In: Check Trade-In Value, Deals & More

Listing the device on Swappa or eBay typically yields the highest return, with used Sprint iPhone 6 models selling for approximately $40 to $80 . Requirements for Buy Back