Evolution of Cards
Cards have been printed and traded for around 140 years. The origins of cards featuring high-profile professionals lie in advertising, as baseball cards were a great way to draw attention to products. They have been used to promote sporting goods and sold with tobacco, candy and gum, but the medium has grown in popularity enough to stand on its own.
Card Condition
Outside of rarity, the condition of the card is the most important factor regarding its value. Mint condition cards are the most valuable. Mint condition means no surface scratches, damage to corners or edges, centered images and statistics or blurry, dull pictures and colors. Older, rare cards can be hard to find in mint condition.
Pricing Authorities
Regarded as the leading authority in information and value of baseball cards is Beckett Media and the Beckett Baseball Card Price Guide. Founded in 1984, Beckett provides information on cards, including pricing, from all years. Another authoritative publication is the SCD Standard Catalog of Baseball Cards, created by Bob Lemke and currently edited by Don Fluckinger.
Honus Wagner
Discussions of rare baseball cards always include the 1909 Honus Wagner. Legend has it that Wagner, a Hall of Fame shortstop who played from 1897 to 1917, was against having his likeness associated with tobacco and got production of the card stopped. Anywhere from 50 to 100 cards are believed to exist. In February 2007, one of the cards sold for $2.3 million before selling for $2.8 million several months later.
Other Rare Cards
The Honus Wagner card is not the only rare card, nor is it the rarest card. According to Cycleback.com, examples of cards that are even rarer than the 1909 Wagner include a 1911 Baltimore News Series Ty Cobb, a 1927 Honey Boy Ice Cream Babe Ruth and a 1920s Otto Treulich &Son Grover Cleveland Alexander. In addition, the Library of Congress has a special collection of 2,100 cards from between 1887 and 1914, part of a collection assembled by Benjamin K. Edwards that eventually found it way to the Library of Congress in 1954.