The way I price mine is estimate the yardage for top & backing plus batting & thread. When I estimate the yardage, I use the higher price for fabric, but always tell them if I can get the fabric on sale then the price will be a little lower. If they don't like my prices, then they can buy all the materials themselves. Then I double that price & add 20 % to that. I also insist on half down ( non refundable) before even starting the project. That way I am not out anything if they decide not to finish paying for it. I have never had a problem with the rest of the payment as they don't want to lose what they have already invested in it. Always insist on full payment before handing over the quilt.