1990 Post baseball card setThe 1990 Post "First Collectors Series" Baseball card set consist of 30 cards Three cards were inserted randomly as a cello pack inside specially marked boxes of Post cereals. A complete set has a book value of about $4.00 in Near Mint - Mint condition. Key cards in the set include: card number 1 - Don Mattingly, card number 2 - Roger Clemens, card number 5 - Tony Gwynn, card number 11 - Nolan Ryan, card number 12 - Mark McGwire, card number 21 - Cal Ripken, and card number 23 - Ken Griffey Jr.