i think i remember seeing at some point that UT-Chattanooga puts you up in their housing for the month......other than that i don't recall anyone else doing it.....but i'm by no means an expert on the subject.
i think more important in the whole process if going to a place that you actually see yourself wanting to be a resident, regardless of cost for the month (within reason of course). both of my aways cost me a nice chunk of change either for lodging, or renting a car for the month, or whatever...but i wouldn't change either one of them. usually the program secretary at any given program can hook you up with a list of more affordable housing in the area, or at least give you a hint if such things exist.
general consensus is that you have the best chance of matching at a place you rotate, so pick them carefully and i think you'll find that being happy for 5 years at a place you like is far more important than saving the $1000 or so that you might spend for housing, etc while you rotate
of course that's just my $0.02