Hello all - I recently bought a 7 Plus, and received an offer via text message from AT&T saying my old 6S could be worth up to $650 in bill credit if I trade it in. I own the phone (bought it outright) and it is unlocked (used AT&T's unlocking service). Current prices on eBay for an unlocked 64GB 6S Plus are around $500, so I am curious. However! The ridiculous thing is if you fill out the form online to do the trade, they quote you a value of $0.00 until you send it in. Then they decide what they plan to give you and you're stuck with that. My phone is in pretty flawless condition, but still. Who's to say they won't just say "okay it's worth $200" after teasing me with this $650 figure. Has anyone done this trade-in process and if so, how much did you actually get from AT&T?