I would figure out what other shops are charging. Pretend to be your customer and ask around to Different shops and go with a competitive rate. For someone to sit here and tell you exactly how much you should charge doesn’t really make a whole lot of sense as you have to go by the area you live in. You could live in a smaller town with more lower income people than someone who lives in a city with higher income people. I’d say do some homework and just call around or see if anyone in your area has their prices posted that way you’re not charging too much or too little you can have a competitive rate.