Think about how much time it takes to make a quilt. Now divide that into the 50-75 dollars you were thinking. You will see that you are not even making close to minimum wage. Often times, people charge 2 to 3 times the cost of the materials. This case, however, is in that grey area concerning relatives. I would tell her that you normally would charge $300, but for this one quilt only, as a special favor, you are only going to charge her whatever.