Go for it, tell her $800 and let her decide. My DD sews for a living making window treatments and charges $25 an hour. She made 8 quilts for my cousin using her father's shirts for the main part and they were small quilts, we would call them lap robes and she charged $50 each. They were about 45 x 60 in size.
You get what you pay for and a quilt made by you for her will be treasured forever.
Carol J.