You can always ask that question but getting a satisfactory answer can be elusive. Values of anything are completely subjective. It depends on how bad the seller wants to sell, how bad the buyer wants to buy, the location of the buyer/seller, the condition of the item, the rarity of the item, etc.. The best thing a potential seller can do, In my opinion, is to look for comps just like real estate. If a similar item sold (not asking price but actual selling price), see what it sold for. If you can't find comps set the price higher than you think it might be worth and see if it sells. If it doesn't sell, lower the price and try again. Or use an auction site that sells similar items and let the market tell you what it's worth.