I believe this happens with any project being sewn, other crafts, paintings, not just quilting. It's amazing how many show up with items to be 'mended' if they know you sew. When I say that will be $10 per hour, I get, 'what, you charge for that?'
We were in a car club for many years that put on a 50's dance annually, I had six poodle skirts, all were wool felt, different colors and different poodle patterns. One had rollar skates, another 45 records.
At least 50 people, mere acquaintences, ask me to make them one. My response, from my purse I pulled the list of materials, handed it to them. The cost of those was $20-25. At the bottom, was my charge for sewing the skirt, $25. It took care of the problem immediately. But many FRIENDS did take me up on it and I made $25 when I did make them.