Hi and welcome to FT. I checked the end of September and while I don't know your dates or restrictions, I noted the cheapest r/t is ~$220. The $119 and $109 fares seem to be prominent for the rest of the week. Someone here on this forum noted that Bing Travel has a predictor tool, which lucky for you (lol) isn't able to predict whether fares will change for this route. However, Bing Travel seems to be a cool site, comparable to the other major search engines.

If your dates are flexible then the $220 ($89 each one-way) seems like a good deal. Now I happen to jet pretty exclusively with jetBlue and recommend them, but it does seem that AirTran has lower fares, so if you are only concerned with fares AirTran has $195 r/t with connection in ATL.

Hope that helps...