I don't detail cars for anyone else, but I'm a firm believer in not underselling yourself. Most people who want someone else to perform services for them, be it car detailing, painting or mowing their lawn are willing to pay the going rate or else they would do it themselves. Don't spend a complete day and use your expensive products and only charge a few bucks. If someone detailed my car like you said you detailed that Jetta, I would certainly expect to pay 150-200 for it. If someone wants you to work for nothing, then they shouldn't be your customer. As the population ages, more and more people (and people of substantial means) will be looking for people to do jobs they can't or won't do themselves. I would expect to earn at least $25/hour plus enough to cover my supplies and other expenses.