I was at NAIA in '99. South Carolina is cheaper than most other parts of the US but still not much cheaper than here.
All depends how you want to live. You could probably scrape by on 100 bucks a week if you dont go out just as you could just about live off 70 quid a week here.
NAIA no longer give the allowance to students, something they neglected to tell us even though it appeared in all the literature they gave us.
By the way, Conway is one of the most awful places on Earth. We lived in Applebys most nights - drink Shiner Bock.