How much to sharpen?
I charge 7-8 USD. But this includes taking the rakers (depth gauges)down to specs, and removing the gullet if needed.
I only sharpen with machines, because the consistency is far better than hand sharpening. I have one machine that only sharpens chisel bit chain square, and another that sharpens chipper and semi-chisel.
I also use a machine (silvey) to take the rakers down. Once again, it is far more accurate, and much quicker (and in the long run, lower cost) than using a file. I have people coming 50 miles for me to sharpen, driving right by several so called saw shops. If they bring the saw, I also check the bar and if needed, square the bar with a Silvey bar rail grinder. This will make bars that you would throw away cut almost like new.