This is a tough spot to be in. I donate about 99% of my quilts, so I know the struggle you are facing.
One of my colleagues fell in love with a quilt I made for my mother. It was attic windows and I used the windows as pictures of my mom and my nephew. She asked if I could do the same thing for her daughter with pics of their dog.
It was about 48x48 with 9 pictures (printed onto fabric) ... Total cost of fabric / batting, etc. was about $120
She paid me $500 total - and it took me about 3 full days to make it.
I told her that was way too much, but she was adamant about what she was paying me.
You can use this is a baseline!