Best Buy is offering a trade-in deal on smartphones starting this Sunday, April 8. It ends May 5, 2012.

During the trade-in deal, shoppers trading in their existing smartphones while purchasing a new smartphone and plan from Best Buy can received a $50 discount on select Motorola smartphones, and up to a $200 Best Buy gift card.

Motorola-Photon-4GThe Motorola smartphones that qualify for the $50 discount during the trade-in deal are the Motorola Atrix 2 on AT&T, the Motorola Photon 4G on Sprint, and the DROID RAZR 4G LTE (16GB Memory) on Verizon Wireless.

We were actually hoping for a wider selection of discounted phones when we first heard about this deal – but at least there’s more to it than just the $50 discount. There’s also the Best Buy gift card. Best Buy tells us that an estimate of your old phone’s trade-in value can be calculated at: Factors that affect the trade-in value include condition, product age, specs, and documentation.

According to Best Buy, the deal is only good at Best Buy stores, not online.