It may be just something that bugs me, but;
Why do people not ask "How long would this take?" instead of "How much should I charge?"
Surely we all know that prices vary dramatically across the country yet time scale on a specific job would be constant, if done to the same standard.
Price at the end of the day is what you are willing to work for, I price differently for the same type of work dependant on whether i have the time to fit it in, to make it worth the extra hassle. If I am quiet my price would be cheaper to greater the chance of getting the work.
How much should i pay for a hoover, a jet wash, a van, YES, but for m,e how much should I charge is a personal choice on what you think you are worth.