Does AT&T still but iPhone's?

They used to take $100 for iPhones. Do they still have that offer?

Yes! If you get a 2 year agreement WITH ATT ONLY.

I bet if you call AT&T customer service they would know, or check their web site.

Call and ask it varies from store to store and if you have a contract with them and are upgrading with them. If your iphone is a 4 or better sell your iphone on ebay or craigslist instead. You will get a lot more for it.