Would appreciate it if you could help me answer the following questions. What is the market for a used unlocked 3GS in mint condition (have a case and screen cover on it)? Why would someone be willing to buy a used unlocked 3GS? Why wouldn't someone just buy a new iPhone 4.0 and unlock it instead of buying a used unlocked 3GS (assuming they have the money)? If I were to purchase a new no-contract 32GB iPhone 4.0, would using it be as simple as inserting the SIM card from my old 3GS?