I picked up an open item unlocked S8 for $537 yesterday from Best Buy. They had it marked at $637 but I had $100 in rewards points expiring soon. Store managers a friend and called when it became available.
A guy bought it, went outside and called Att from his original phone and came back in to return it before leaving the parking lot. Apparently Att told him it wouldn't work on their service so he bought an Att version. Box hadn't even been opened.