It does come with a SIM card slot, I believe it would be unlocked soon but I don't know how to do it now. $49.99 for Moto G LTE, it is steal.
http://www.uscellular.com/uscellular/cell-phones/showPhoneDetails.jsp?productId=prod2740116
http://www.uscellular.com/uscellular/cell-phones/showPhoneDetails.jsp?productId=prod2740116