The price and max skill might depend on the school its quality and maybe location for example the Capitals should have the best and schools. It should be paid for only 1 single character and access to only 1 class for one in-game week or month or how long one semester might be.
For combat skills id like to see an academy or barracks but academies should be limited to Capitals only. The acadamy should give militia training, soldier training and elite training. Also the Weapon skills should get special classes or courses. Like the schools it should be 1 trainee for 1 charge.
A cheaper version of a class or school should be an apprenticeship at your local weapon- / armorsmith or a guards man etc. but that would have less quality training than the school.
Special skills like Material-Arts should get special teachers who roam and look for new apprentices or whatever you can imagine.
Some stuff like the Holy-hate against women and Scorchlanders should limit the visitors of schools to Greenlander men in Holy lands and other limits for other nations races....