Two good rare record price guides available online are Popsike.con and MusicPriceGuide.com. Both offer price guides without fees or membership, and both use information from auctions to provide prices.
Popsike.com states that there are no set prices for collectible records, but having reference points for prices is great when trying to value a record or a collection of records. Users can search for records by artist and label.
MusicPriceGuide.com also features auction prices and has several tips in the guide section for customers valuing records or collections. The site also offers classified ads for buying and selling records, as well as a section advertising record fairs worldwide.