I think depending what she hands you. Will the quilt be ready for binding, squared off; is the binding cut and seamed, ironed; has the other fabric been washed, if so the binding should be washed and ironed; they furnish fabric, thread etc. For a business I don't think $.15 - .25 a foot (CORRECTION PER INCH) is too much. Businesses don't ask customers what to charge, you know what you will need. It would be harder to charge more once you started, maybe you could have a couple of specials for the first month, get your name out there while you're trying to get established.