Walmart has announced its own new wireless service brand, placing an emphasis on faimly savings. Walmart will launch Walmart Family Mobile as a post-paid plan available without a contract or multi-year commitment. The company says it offers a family of three savings of up to $1,200 a year when compared to leading unlimited talk and text plans. T-Mobile's network is being used, but the service will be sold exclusively through Walmart. The first line is $45 a month,