Lstorm - some of the best CFI's at my FBO when I was training were PT guys with other jobs. They were the best because they weren't time building, but doing what they loved on the side. I'd encourage you to do that.

Ninja - I'd encourage you to go to your FBO and ask the local CFI's at the airport where you're working for free how many hours they're getting and what kind of money they're making for the last couple of months. Maybe when you see that while an extra 20-30 bucks a month might be chump change to you, it's the difference between Ramen noodles and PBJ for a guy starving to pay his dues so he can move on. You may think the few students you're teaching aren't enough to make a difference, but I guarantee they would be a big difference to the starving CFI at your local FBO from whom you're stealing clients. The reason no one can earn a living as a full time CFI is because whenever they try to justify charging more for their services some douche bag comes along giving the same services for free. If you want to help the profession, provide extraordinary instruction at above average prices, driving up the wages while giving your students a bargain for their money. At the very least charge what the full time guys do and just be better. Otherwise, you're stealing from guys who depend on those students to survive.