Years ago when I learned to fly, I really couldn't afford to go out and purchase all of the equipment, the guys at the field I hung out at gave me an old Midwest ugly stick, let me borrow a motor and a radio and taught me to fly (can you remember the "pass the x-mitter days" before buddy cords ??)
I'm in the position now to pass that on...I would never take money from somebody to teach them to fly.
Every once in a while I'll come across a trainer in a trade that I really have no use for, but I'll stick it in the garage until somebody comes along who is in a similar position I was in and give it to them......in my opinion, that's what the spirit of this whole HOBBY is about.....
If I need to get paid, I'll sit here in my office and surf RCU !!