Baseball card prices can be found on a variety of websites. Beckett, Tuffstuff, Free Baseball Cards Price Guide, Vintage Card Prices and Professional Sports Authenticator all have price lists for a wide selection of individual baseball cards and decks.
Beckett has a large database of cards dating back to 1857. Its online pricing guide includes cards from the major, minor, professional, college and foreign leagues. They also offer pricing guides for autographed merchandise and memorabilia. Access to their guides requires a one-month, three-month, six-month or 12-month subscription.
Tuffstuff's online magazine offers free access to a 196-page price guide to baseball sets and singles. The guide includes a selection of manufacturers and top baseball players, past and present.
Free Baseball Cards Price Guide offers free price guides for baseball cards starting from the 1940s up to 2010. Its website advertises that what sets it apart from other price guides is that it lists prices close to street value, which means cards can be bought and sold near or at the actual prices they list.
Vintage Card Prices has a searchable database of baseball card values that are listed in real time. Searches can be done by keyword, player name, card type or set name.
Professional Sports Authenticator lists baseball card values for cards dating from the late 1880s to cards in 2014.