In my part of the country there is a very large disparity in CFI pay. Some schools start their CFIs at $8/hr and some pay $50/hr, and that's for the same crappy old 172. I was fortunate enough to work for two schools full time as a contract instructor and one payed $32/hr and the other payed $50/hr. I think the reason students are willing to pay higher instruction rates is a higher caliber of instruction. When students recognize that an instructor is not there just to build hours they will pay more for the instruction they receive. And while instruction is typically seen as the bottom of the ladder it should be treated as a profession and important part of one's career. While I did instruct as a means to fill my logbook I also used it as a way to gain experience and knowledge. I look back at my time as a full time instructor with fondness, and I jump at the chance to instruct whenever I get the chance. Instructors really do deserve to be well payed.