Sprint yesterday revealed that its deal to offer the iPhone 4S is a 4-year agreement that will cost it US$15.5 billion. The US operator has come in for criticism over the cost of the deal but claims that it will “outperform” that contract. "We expect the lifetime value of a typical iPhone customer to be at least 50 percent – yes, at least 50 percent – greater than a typical smartphone user, driven primarily by more efficient use of our network and lower churn," said CEO Dan Hesse during the firm’s quarterly financial call. It expects to sell more than 1 million iPhones in the fourth quarter.