If it were my niece and my sister that was getting the quilt, I would not be charging anything to make the quilt. I also have a large stash of fabric so my niece would be "shopping" for fabric at my house. She'd pick the pattern (with a few suggestions) and the colours and I'd stitch. I know not every family operates this way and perhaps you are not in a position to do this for your niece and sister. I don't charge family and my niece will "pay" me back some time by keeping my dog when we are away.