Royals prospect Alex Gordon is going for a pretty price on cardboard these days. Gordon, who was taken second overall out of the University of Nebraska in the 2005 draft, was inadvertently featured on a Topps baseball card for 2006 rookies. The only problem is he shouldn’t have been on the card at all. The Major League Baseball Players Association stipulates that a player who hasn’t played in a game or isn’t on the current season’s 25-man roster can’t have a card.

Topps realized the mistake and stopped printing, but about 100 of them survived and made their way to the general public. Some are selling for $1,000 dollars.