Money and Yoga is a different topic. Even among the Himalayan gurus in the past there was the tradition of gurudakshina : it was something like “Now get married and you will teach Yoga until the end of your life”, “Build me a house”, “Now get a job and give me this amount of money, so that I can carry on teaching and sustaining my family/ashram…”, “Give me a cow…”. Even in the ashrams, usually disciples gave everything they had or earned to the guru who was in charge of the community.
Giving teachings and receiving money is not something necessarily sacrilegious though it is easy to denature Yoga this way, it depends on the cases. There are different modalities of payment for instance everyone gives a chosen amount in an envelope, there can be a price fixed according to the income aso… There are the examples of Theravada monks teaching Theravada Buddhism for free but they are sustained materially by the lay community.
A few years back, I had Sanskrit classes for free with a teacher in a Vedantic centre. He is a nice man with a realization of a guru IMO. He is retired with a good pension, he asked nothing but he did not need to get extra money to live neither. Even in this case, we, students, used to offer money discreetly in an envelope though it was a difficult time for me financially. We did not take him for granted, and probably he gave most of the money if not everything to the Vedantic centre for its functioning.
Philippe