If you want any retunr on you time...I suggest 4 times the cost of materials. Other quilters will give you suggestions, too. This way you will be paid for SOME of the time you're investing into the projects.
If you DON"T want to do the project(s), charge a crazy amount of money and just watch the jaws drop. That's what I do. If I don't want to do the quilt, I say I charge 10.00 and hour and there will be a minimum of 40 hours of work into the baby quilt.