I have an opportunity to purchase a set of 6 panels with power supplies and the brackets to attach the panels together. They have been in the same house for 30+ years and are in excellent working and physical condition. Only minor issues are some very small stains in the grille cloths on 2 of the panels - hardly noticeable. My question is what are they worth? I know the old adage, "...worth whatever someone will pay..." but I don't want to overpay. Thank you to any members who respond - much appreciated!