If you're thinking of surprising your sweetie this Valentine's Day with a new phone, T-Mobile has an promotion you might be interested in. On February 11th, the carrier is offering every one of its 4G smartphones—and a few Android tablets to boot—for free.

Well, not literally free. You won't be able to walk into a store, grab a 4G handset off the shelf and be on your merry way—I'm pretty sure there are laws against that—you will still have to pay for the phone. But T-Mobile is offering a mail-in rebate that drops the total cost back to nil.

The offer is available for both new and upgrade-eligible customers, will require a 2-year contract (like you didn't see that coming), and will be in effect for one day only. Reportedly, the Samsung Galaxy S II, BlackBerry Bold 9900, HTC Amaze 4G, and Nokia Lumia 710, as well as the SpringBoard tablet and Sonic 4G hotspot will be among those up for grabs. Check out the T-Mobile Valentine's Day Sale website for a complete list of offered devices. [TMoNews via Android Community via Electronista]