The cheapest route to a 4G-LTE smartphone, carrier-locked LG Optimus F3, will arrive on T-Mobile's product stack in a week from now, on August 7th. The phone is already available on Sprint and MetroPCS. You can take home a T-Mobile Optimus F3 for $0 upfront.

　　Optimus F3 offers a 4-inch screen WVGA (800 x 480 pixels) resolution, a 5-megapixel main camera, a 1-megapixel front-facing one, and a pretty robust set hardware under the hood: Snapdragon 400 dual-core SoC, 1 GB of RAM, 4 GB of expandable storage, Android 4.1 "Jelly Bean," and a mammoth 2,460 mAh battery that's clearly overpowered for a device of this category, which is a good thing.