OK so I have an iPhone 4 that I want to get a quick $200 for from AT&T. The problem, however, is that none of the stores in my area have the 6 I'm looking for. Or frankly any 64gb 6 at all really. So is it possible to trade-in my 4 at AT&T and buy the new phone at the Apple store? And my second question, is the $40 upgrade / activation fee payable when you buy the phone or does it appear on your next monthly bill? Thanks for reading.