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Look for price guides specializing in items like yours. Choose the right price guide. Take pricing from price guides with a grain of salt.
A price guide is a book full of descriptions of specific types of items (antique furniture, baseball cards, stamps, etc.), along with the prices you can expect to get for each item. The best guide to use will depend on the kind of item you want to sell.   Kovel’s, in particular, is a highly respected publisher of price guides.  Many libraries have price guides on their shelves, too. Make sure that your price guide is up-to-date and recent. Because the prices of antiques and collectibles change depending on markets, an outdated price guide will not give you an accurate idea of how much your item is worth. The best price guides will also include plenty of pictures of the items included in its pages. The descriptions and values listed in price guides are general estimates. They cannot account for the wide variations in the quality and condition of specific items, economic conditions, or demand in specific regions.