Although there is a certain benefit to both of you to make a deal with friends, this can be a setup for irreparable damage to a friendship.  If you’re going to do a deal with someone close to you or with someone like your boss or an employee, make SURE that there’s an independent pro involved to confirm all of the statements of grading, reports of condition, etc. Hire an appraiser.  Actually,insist that the buyer hire an appraiser and it shouldn’t be the same one that you hired.  If you're not careful this can be far more costly than you ever imagined.