I haven't read all the responses here, but my first reaction is you might be walking a thin line here. You made this quilt with a ton of love and dollars. It was your choice to splurge on the gorgeous but costly batiks on a quilt this large. But no amount of money is worth possibly offending your son and future daughter-in-law. It might take the joy right out of receiving the gift and spoil your very best intentions if you put a dollar value on the quilt. They also could chose to put the quilt away, afraid to use because of something happening and that would be such a shame. If you want it appraised, that's fine, but I'd keep and produce it only if necessary due to an unforeseen catastrophy. Nothing wrong in printing something out with laundry directions and maybe including a box of color catchers. I hope I haven't offended you with my honesty.