It doesn't matter how much you charge, as long as you are up-front about it. Telling the customer that there is a surprise diagnostic fee is going to be upsetting, as is a 300 percent mark-up on material.
I get the same complaints as the rest of you do, but I always try to put myself in the customer's position. For example, what if a mechanic quoted $100 to replace a tire, then charged $300 for a $100 tire. I'd be pissed, wouldn't you?
