I think $400-$500 is reasonable. I recently went on the Keepsake Quilting website and was astonished at what some people were charging for their quilts. A few years ago while visiting the Keepsake store, I saw a log cabin wreath (ala Eleanor Burns) quilt hanging up for sale with a price of $96, and the fabric wasn't even all that special. I have made dozens of them and sold them for $35 at my church fair, some people thought it reasonable and others thought it was too high. $50 to me would have been more reasonable price, but having said that, in that area of NH with lots of summer homes and summer tourists, she probably got that much. Don't be afraid to ask a reasonable price for your work and materials.