1961 Roger Maris Baseball Card Ad from the Front Panel of a Post Cereal Box. Lot 154. 1961 Roger Maris Baseball Card Ad from the Front Panel of a Post Cereal Box. This 1 7/8” x 3” ad appeared on the front panel of a Post Cereal box in 1961. It called attention to the cards on the back. Ex. Winning Bid $30. Back to List Winning Bid $30 Back to List