There were some really great responses. Murphy you were so right on and ScrewyStewy also. I work for a Parkinsons clinic in WA state and one of the Doctors asked me to make a quilt for her son's new room. I told her that Materials plus time for stitch in the ditch if she wanted it professional quilted it would have to be shipped out to be done. I told her $10.00 hour labor with a minimum of 25 hours. I typed up a contract and had her sign it (with no problem) Don't forget to charge for your time to shop and prep.
Most people think you can throw them together and it won't cost much, but what I have done for simple patterns and SID I go on the web and find some of the amish quilts with simple blocks and put the link on the contract.....Usually the amish quilts are considerably upward priced.
hope this helps.............but before you start have them sign the contract and get a deposit. (Usually the price of the materials.)
Robert