I once agreed to make a quilt for a friend to be used as a fund raiser. This person agreed to pay for the quilting, and materials, what great as far as I was concerned. I did not charge for my labor (that was my contribution). I kept very strict track of my time and had over 200 hours on this quilt. The cost of the materials (and the LAQ) was about $450.00. It turned out to be a really pretty quilt (I almost didn't want to give it away). The fund raising proceeded and only pulled in $480. This was heartbreaking, but brought home the fact that most people have NO CLUE about the cost of materials and the time it takes to make a quilt. If I had charged for the labor also, the price would have been prohibative.
I guess the point to all of this is, don't agree to do a quilt for someone else unless you make sure that they understand how much money will be involved. DO NOT FORGET TO CHARGE FOR YOUR LABOR and DO NOT FORGET TO CHARGE FOR MATERIALS.
Good luck and keep it fun.