My mom and I both have an Iphone, hers is a 8G 3G that's 1 year old, and mine is a 16G 3GS that's about 6 months. Her phone used to mine but around christmas I got my new one and she got my old one, since it wasn't time for my upgrade we added a another line for my grandma and gave her my mom's older phone, my mom got my old one, and I got a new one. Well now I want an Iphone 4 for my birthday, so my mom is going to sell hers and I'm giving her my old one. And it's not time for my upgrade so how much would it cost to buy a 16G Iphone 4 without it being an upgrade? I really don't want to have to pay over $200, so since my mom is getting rid of hers, then could we disconnect her number (how much would that cost?) and then add another line and make if for my old phone, which will now be hers?