As a handquilter for hire I always give the customer a price sheet that tells how much per square inch for the quilting and brakes it down into various sizes etc. I also state that the closeness of the quilting raises the price. and also list those charges. I list charges for binding, marking if they have a particular pattern in mind, and my expenses for batting and backing if I provide those items. I also require a $50 deposit.
The only kind of quilt I would make for hire from start to finish is a wholecloth or preprinted panel.
My major customer was a lady who was also a musuem curator who now owns her own custom framing business. I finished at least 6 quilts for her that her grandmother had pieced the tops. She understood handwork and was more than willing to pay.