The cellphone carrier announced Monday that all T-Mobile customers with a "Simple Choice" plan can now receive a free mini cell tower for their home. The 8.5-inch square gadget blasts out T-Mobile's 4G-LTE network to a 3,000-square-foot radius.

T-Mobile has done this kind of thing before. It previously gave out free Wi-Fi routers that allowed customers to make calls and texts over their home Wi-Fi networks.

What T-Mobile announced Monday is different: The mini tower (T-Mobile is calling it a CellSpot), lets customers connect to T-Mobile's cellular network -- not Wi-Fi. That means in places where they received one or no "bars" of service, they'll now get a full, speedy connection.

Other carriers have similar offerings, but they cost hundreds of dollars. T-Mobile is giving them away for free (OK, for a $25 refundable deposit).