my Uncle has both iphone 3G and Iphone 1 gen. he got his activated in the store. turns out now he doesn't want it anymore he wants to go back to his 1st gen iphone. so he just change the SIM card and his fisrt gen. And he says he will sale his iphone 3G to me for $100 but can i get it activated in itunes by swicthing my SIM card (my is 3G) will it work what will the charges be? please tell me step by step