Here's what I've learned....
If Tennessee is like Kentucky, there isn't much information on sailing. There is a school on Kentucky Lake that I believe is ASA based, as I recall. Other than that, all I can find is along the coast, and as you say, classes are rather costly. My goal, as I assume yours is, was to shoot for bareboat charterer acceptance. After seeking similar information, I've ultimately been guided to the US Power Squadrons route. I'm taking the basic classes (America's Boating Course, Seamanship, etc.) locally. In fact, I'm doing as much as I can via home study, taking tests with the local squadrons. I'm told that these certificates will translate somehow into the ASA and US Sail certification programs, helping with at least some of the training, and that many of the bareboat charterers hold the US Power Squadrons certifications in comprably high regard. I still intend someday to take some of the practical sailing courses, which US Power Squadrons just can't duplicate...at least around here. I found that I could not get responsive information from ASA, US Sail, US Coast Guard Auxilliary, or US Power Squdrons until I registerd for the America's Boating Course, after which time the later two organizations began to contact me. Check out the attached URL for more information. Good luck!!