Essentially, in this deal, you're renting the phone instead of buying it outright. Sprint Corp. (S) introduced an "iPhone for Life" plan that lets customers get a new version of Apple Inc. (AAPL)'s smartphone every two years as it moves to win back customers lost to rivals including T-Mobile US Inc. (TMUS) The service costs $70 a month and includes unlimited data, Sprint said on its website yesterday. Customers make no initial payment for the phone or related taxes on the device because they are essentially renting it, the company said. Chief Executive Officer Marcelo Claure is counting on the new iPhone 6 to help Sprint start adding subscribers again after a seven-year streak of customer losses. By tying promotions to Apple's device, Sprint is following in the footsteps of controlling shareholder SoftBank Corp. (9984), which used an exclusive iPhone deal to gain market share in Japan. "I challenge anyone in this industry to beat this," Claure said in an interview yesterday. "Nobody is going to do it."