The Allen & Ginter's World's Champions tobacco card set was released in 1887 and is considered the first significant card set issued. There were ten ballplayers in the 50 card set (which also included boxers, billiard players, wrestlers, and the like) and the cards were inserted in packs of Allen & Ginter cigarettes. A complete set of the ten ballplayers in the right condition is valued at over $78,000.
Above is the Bob Caruthers card.
A quick note: I want to welcome all the readers from Whiteyball to my little blog and thank Dustin for the link. Whiteyball is one of my favorite sites for info on all things Birds On The Bat.