I typically charge by vehicle size, and what exactly they want done. For a clay, and seal, or clay and wax, plus obvious trim and stuff, and interior, I'll usually start at 150 for a midsize car, 175-200 on a small-mid size suv, and 250 for a full size suv. If it's really bad, I may charge a little more. If I have to remove major stains in the carpet or upholstery, the price will go up. Same for if they want the engine compartment cleaned up. For any machine polishing work, I'll usually start at about 350, and go up from there depending on the size and severity. I don't claim to be a professional, but I typically do a much better job than any detail shop in town, and I try to keep my prices competitive for the sake of keeping a steady flow of business. Hope that's helpful.