I think $55 to have it appraised is a bargain. Since it's been juried into the show, that will increase its value significantly. As others have said, an official appraisal will protect you in case the quilt is lost in the mail (I know you said you don't anticipate it will go anywhere else, but it has to come home to you first, right? Plus, you may decide to enter it in other shows!). Additionally, an appraisal may be helpful with your homeowners policy in case of fire, flooding, theft, etc. (depending on your policy, of course - speak to your agent.)