Im kinda interested in the same thing. I want to go to a formal school for at least 3-4 days to practice and practice. Im only 24 but I would like to work for a mini tour in the next year or two. But honestly the best experience your going to get is with a 1-on-1 lesson scenerio. Because you can ask more questions and learn more in less time.
If your heart is set on a school the cheapest I found (with best reputation) was
http://www.ritson-sole.com/. And they have locations in ~6 states so you can go to the one closest to you. I know they made it in the top 25 schools in Golf Digest though I would put little merit into that because money can influence who gets listed. But the curriculum for the classes sound very good. On that note do some homework and see if it fits the budget. I plan to go to either the myrtle beach or New York location next spring.