I recently sent an Elmar 50/3.5 with a stuck focus ring to Oleg. When I asked him for an estimate by email he told me it would not be in excess of $20. Postage to Russia was $8, Oleg charged $13 to fix the focus ring and do a complete CLA, and postage back from Russia was $10. Total invested was $34 and it took four weeks including transit time. I had no problems, and was very pleased with the whole experience.
Oleg charges $70 for a CLA on an LTM Leica. His website is
http://www.okvintagecamera.com/repair.html for prices. His email address is there as well, and he is very responsive.