When I got my original iPhone G1 I setup the iPhone as Pick-Your-Plan prepaid with unlimited data. When the iPhone 3GS and then 4 came out, I cut down my SIM and continued using the same plan with the iPhone 4. I called and spoke with AT&T Customer service. The AT&T rep said she checked the iPhone 5 white paper and a Pick-Your-Plan iPhone prepaid account can be grandfathered to the iPhone 5. She said I am very lucky because not many people still have a Prepaid Pick-Your-Plan iPhone. She said I can buy the iPhone 5 full price and they will provision my prepaid account to the iPhone 5 SIM and provision LTE unlimited data to grandfather my unlimited data plan. I was shocked and did not believe it and had her verify it with a manager. So if there is anyone else with a Pick-Your-Plan Prepaid unlimited data iPhone they will allow you to continue using the same account for the iPhone 5.