I agree with Toonces...Maybe.

I started out charging $20 per hour (handshake to handshake) which was what most new folks were charging. As I gained experience and a good reputation through word of mouth I gradually raised rates over the years, because I could. I also charged more for Aerobatics or Mountain Flying because there weren't many CFI's qualified to teach that stuff.

If money is tight and you can find another instructor that you get along with and learn from, you should probably jump ship. I'd also be honest with your original instructor about the reason. Remember that you are the customer in this equation, he needs to earn your money.