Has anyone used gazelle.com to sell their used iPhones? In preparation for switching from AT&T to Verizon I want to sell my 4 to pay the ETF. I went to gazelle.com and they have offered me $420 for my iPhone 4 32 GB plus I got an additional $45 for using a promo code I had. It seems too good to be true. This would more than pay off my ETF plus buy my new iPhone on Verizon. Has anyone dealt with this company? Any gotchas I should be aware of. I've told them to go ahead and send me the box to ship my iPhone in.