Sprint has again dropped the price of the iPhone 4S, effectively lopping $100 off the cost by offering a $100 American Express Reward Card along with the purchase of a 16GB model and a two-year activation. Just over a week ago, the nation's third-largest carrier cut the price of a 16GB model by $50 to $150. The addition of the Reward Card means the carrier is effectively selling the latest version of Apple's phone for $50, far below the other national carriers.
