I got my phone on the Att Next plan. I got a 6 on launch day. Anyone care to guess how much I can sell my iPhone 6 for once the 6s plus is out? I'm trying to decide if I should sell it and get the plus since I do love the size of the plus. I plan to always pay per month since I will upgrade at least every two years. Just wondering how much I might be out if I do it. Someone must have calculated this to get an idea.