It appears that Mississippi State University is no longer the cheapest AACSB online MBA at $375! Western Kentucky University is $360 per credit http://www.wku.edu/emba/, Although it is an eMBA. -For my money I'd spend the extra $15 a credit, to not worry about the little e designation.
If you are a Florida resident, FAU is really cheap. Although I think there are other state schools like that as well.
