To answer the OP's questions:
Originally Posted By: WhyMe
how much do you guys pay for rotor turning?
My local race oriented machine shop charges $25/disc for turning. Other garages charge a little less, but I now only use the race shop.
When they are done the flatness (parallelism) and runout tolerance measurements are beneath the ability of my Starrett equipment to measure- the surface finish is greater than the tolerance!
Do NOT expect these kind of results from Pep Boys.
Originally Posted By: WhyMe
so are these guys just pricing rotor turning to get you to buy a new rotor instead?
They are pricing rotor turning at a level to make a profit, considering: labor, machine time, and tooling wear.
For some larger trucks, older and rarer vehicles, and for performance equipment, it is more economical to turn brake drums and rotors than replacing them. Where common mass-market rotors are available, turning is a hard sell.
To answer the unasked question, which is better for the car, turning or replacement? It depends secondarily on the quality of the old versus new, and primarily on the resulting measurements, both off and on the vehicle. Since the repair industry has an obstinant resistance to actually measuring these things (simple and cheap to do, it's in EVERY FACTORY SERVICE MANUAL but HEY IT TAKES 5 MINUTES NO WAY! I'M ON THE CLOCK), few people actually know. But they are happy to opine.
"Without data you're just another person with an opinion." -Deming