When Rickey was playing for the Mets in 1999, a company named Famous Fixins produced a line of Amazin' Mets Frosted Flakes. The box was labeled as a Premiere Box, and as a "Limited Collector's Series" with only 250,000 printed. That seems like a lot of cereal to me, but it was limited in their eyes.
The Mets box also featured other Mets, including Al Leiter, Mike Piazza, John Olerud, Edgardo Alfonzo, Robin Ventura, Rey Ordonez, and John Franco. The Famous Fixins company produced a wide variety of collectible sport themed cereals, including Cal Ripken's "Cal's Classic O's" and Alex Rodriguez's "A-Rod's 40-40 Crunch."
The following picture is from the back of a 4" x 6" card promoting the cereal. The front of the card features the cover of the box (so there was no need to show it again), while the back of the card features information on a sweepstakes that you could enter by purchasing the cereal.