I charge $65 + parts +shipping for a clean, oil and polish and I go over and above what the other places do. I give the machine the complete spa treatment after a tear down. Then after a thorough cleaning I reassemble the machine set the tensions with a gauge and then I will give it a good polish. Then you will receive a piece of broadcloth with all of the stitch functions demonstrated on the cloth to make sure it works correctly and to let you know that I tested the machine thoroughly.
Most shops that I have been in just take compressed air blow the machine out oil it up and bam they are done in 10 minutes or less. Thats why you have a lot of complaining customers and messed up machines.
Billy