Before agreeing to anything, have them look at patterns you think you can handle. When they have one they like, figure out the yardage required and have them go with you to buy the fabric (they pay). This usually helps to weed out all but the serious requests. If they get passed that, figure out how long it while take you and give them an estimate for your time and expertise. Have an agreed upon price and if they fail to pay at time of pick-up you are just out your labour and you can keep the quilt until they do pay you.