T-Mobile will be having a killer sale this weekend for one day only. The mobile retailer will have all phones and the Springboard and G-Slate tablets for free on Saturday, February 11th. They are calling it a Valentine's day sale, which is smart timing coming a few days before the event. It's important to note that this offer is via a "mail-in rebate" so keep that in mind when showing up to the store, and bring the full subsidy price accordingly. Here's a video to kick off the sale above.