I did a search on that within the past year and found that Boys to Men is one of the lowest cost of all.
Their tuition was $3,500 and that included even room and board.
http://prepsports.stltoday.com/ssi/...A0C6219ACB1BED56862570B40059C493?OpenDocument
But BTMA is not elite, it isn't graduating scholars, and they use simple rented space and gyms, so kids keep costs down.
The developer of BTMA obviously does not want excess costs to cover.
But most others are in the $4000-$8000+ range with the very elite academic schools at $20,000 to $30,000
(per this story in Forbes)
http://www.forbes.com/2006/12/09/private-schools-most-expensive-biz-cx_tvr_1211prep.html
Here are some specific examples:
Brewster Academy - Tuition= $21,760, Tuition with board=$36,730
http://www.brewsteracademy.org/applying/a_valuable_investment/tuition/index.html
Oak Hill - Tuition with board=$18,300.00
http://www.oak-hill.net/fees.htm
South Kent - Tuition=$19,900, Tuition with board=$29,000
http://www.boardingschoolreview.com/school_ov/school_id/127
Winchendon Prep - Tuition=$ 21,250, Tuition with board=$35,500
http://www.boardingschoolreview.com/school_ov/school_id/301
As to who pays....your guess is as good as mine, but here is my guess.
I think in many cases it is the people I have referred to as "handlers" or AAU people, or "coaches" who might just somehow have an agreement to get their investment back if and when their preppies hit the big payday.