I'm hoping for a Black Friday $0 deal. In fact I've got Amazon's AT&T S3 page saved in my browser and I check it every day for a lower price. It's $99 right now and I'm guessing it will drop to $49 for Black Friday but $0 would be sweet. I got my Captivate at Radio Shack 2 years ago on Black Friday for $0 & waived activation so they're a $0 Black Friday possibility too but they're not currently selling AT&T phones online, only in the store. One way or the other, $49 or $0 I'm looking forward to my new S3 Black Friday.
I actually think you're better off buying from Amazon, Best Buy, Radio Shack etc. than from AT&T because if you need a replacement phone within the 30 day period you'll get another new phone whereas AT&T generally replaces new phones with refurbs. Also, if you have an unlimited data plan you need to call AT&T to retain it if you buy the phone from a third party online because buying online they sometimes don't offer the grandfathered unlimited data plan option. Also tell AT&T you want the activation fee waived if you were charged one and they generally will accommodate you as a courtesy.