I have been asked many times how much I would charge to make a quilt, and I always say somewhere around $500 to $750, depending on the size of the quilt, and I will choose the pattern and take you to the LQS so that you can pick out and pay for all the fabrics (top, backing, binding, batting), which will run somewhere around $350 to $400. Then they ask if the cost of the fabrics decreases the $500 to $750, and I say NO, that is for the thread, wear and tear on my tools and my labor. Then I ask when they want to meet at the LQS. I have not yet had a taker. If someone agreed to those terms, I would get a written contract that specified a non-refundable 50% deposit on the fee (they are paying for the fabrics), a deadline for their benefit, and a deadline for them to pick up the quilt and pay for it; if they don't meet the deadline, the quilt becomes mine.
The Good Book says a laborer is worthy of her hire. Do not hesitate to ask for what your time, talent and experience are worth.