The Apple iPhone is expensive for carriers because of the subsidy that each postpaid carrier pays to keep 16GB version of the Apple iPhone 5 priced at $199.99 in the U.S. The carrier's CEO Mary Dillon is hoping that by offering the most popular smartphone in the U.S., the mobile operator can reverse the decline in contract subscribers.
Apple requires carriers to purchase a minimum amount of units and US Cellular will be getting 2 million iPhones, which will require them to pay Apple $1.2 billion over three years. Unfortunately US Cellular has not specified the launch date for the iPhone or the models that they will carry, but with the 4G LTE network the carrier has recently established, they are definitely ready to bring the iPhone to their network.
source - Associated Press