Sprint is launching an aggressive new promotion, offering customers a $400 store credit if they switch from another carrier, according to Phonearena. The deal is available to customers who sign a two-year contract and activate at least three lines on an Everything Data Share or Simply Everything Data plan. The promotion requires users to transfer one line from any competing carrier in the US, though Sprint-owned subsidiaries like Virgin Mobile and Boost Mobile are ineligible. This isn't the first time Sprint has tried to lure subscribers away from other carriers — back in March the carrier offered customers who switched a $125 credit. Sprint's newest promotion is only available in-store, and runs from this Sunday, August 19th through September 15th.