Try this! I worked for a company that charged $100/hr. and mat. +200% All work was done pre quote.
What I found was that I would get about the same # of rejects as I would for a lesser price. I think that most people feel committed when they make the phone call.
Now that I am on my own I use a different lower rate structure. Once I am in a house I can Sell and typically turn a 1 hour job into a 3-4 hour job and walk away with $4-500 and references.
The money you take in is 1/3 from the work you are doing and 2/3's what extra work you can sell.
