MA is my hobby. I have a day job and I'm certainly not an MA "pro". I just run a small club. I started it up again about eight years back when the previous instructor, my si-dai (younger kung-fu brother) moved away. Rent, insurance, inflated association dues, and the cost of my own continued training (which involves traveling out of state) all add up to more than I receive in student tuition. In good years I've broken even.
More recently, I've had to kick in around $100 dollars a month to keep things going. I still do it because I enjoy it, and because if I didn't, there would be nobody teaching my lineage of WC in my area. So, it's a hobby and a personal commitment. And it costs less than golf, skiing, or a lot of other hobbies.