How far south of Atlanta are you looking to go? We stayed in Macon, GA (because that is where our van broke down on our way to Disney last week), and they have a ton of inexpensive hotels. They are all on Riverside drive right off of 75. We stayed at two different hotels, Howard Johnson (I wouldn't recommend this one, it was kind of dirty), and Comfort Inn (this one was decent). The area wasn't bad at all, and the hotels seemed to be around $60.00 for a room (we had 4 adults that shared a room). There was also a Holiday Inn Express, and quite a few other hotels as well. You might even be able to get the rooms cheaper if you booked in advance. Due to car problems, we had to just drop in and take whatever rate they had to offer, and it was still only about $65.00. Travelocity or Expedia might be a lot cheaper.