It is my belief that a real teacher is not guided by money but what he can teach to someone who is willing to learn.
Some of my teachers have never asked for money and so I have left some in an envelope for them.
I appreciate many schools are run as a business, or as a supplementary income stream, but even in business there has to be a loss leader from time to time. I dont think precedents come into it. Either a teacher wants to pass on his knowledge or not. I dont think you can put a price on it.
Osu
Trevor Gilbert
("If I had to select one quality, one personal characteristic that I regard as being most highly correlated with success, whatever the field, I would pick the trait of persistence. Determination. The will to endure to the end, to get knocked down seventy times and get up off the floor saying "Here goes number seventy-one" - Richard M. DeVos)