Early this year I won an iPhone at a company event. Since I didn't need it, I decided to sell it. I discovered that it was locked on Sprint (now T-Mobile). I don't use Sprint. The discussion with Sprint revealed that they required me to have the iPhone on their network for 60 days and then they would unlock it. I signed up, left the iPhone powered on but idle, paid for the 2 months. After 60 days I contacted Sprint and they unlocked it. Then I sold the iPhone.