AT&T is selling the Iphone 6 16gb , any color for $552.49 , it may be certified like-new condition but its $100 off retail price for a new one and its no contract. More info can be found here :

*Waived Activation. Excludes 2-yr wireless agmts. No-annual-contract pricing qualifying credit and qualified monthly wireless service plans (voice & Data). Limit 5 iPhone devices per household when ordering online. Up to $25 savings: Savings on Mobile Share Value monthly pricing is only available on a no annual service contract line (AT&T Next, bring your own, pay full price, month-to-month), and is not available on a 2-year wireless contract. If you are currently receiving this discount and upgrade to a new 2-year agreement, the discount will be lost. If you want to continue to receive the discount, you must upgrade with AT&T Next or pay full price for your smartphone.

http://www.att.com/cellphones/iphone/iphone-6-refurb.html#sku=sku7461174

They also have the 64GB for $637.49 and the 128GB for $722.49 .