I can understand the dilemma. As a teacher of dance I often taught classes that had no fees. I taught the classes because I love dance so much and thought that was enough of a reason. The problem is that to support the teaching of those classes I had to look for other sources of finance and that resulted in a compromise of the quality of my teaching in the free classes because of lack of preparation time. I could have continued in that way but it did not sit right with me and my whole practice has changed because of that. I have never attended a dance lesson that I did not pay for and I would hope that any lesson I gave would receive the same consideration. It is a very tough question to answer without being criticized. In Australia I cannot teach anything in a public place without insurance. Insurance costs money. There are other compliances too that cost money e.g. council permits and hire fees to hold an activity in a public venue. They are the hidden costs that students don’t know.