C-3P0's Cereal hit grocery store shelves in 1984 and enjoyed modest success. They weren't a tremendous hit, but the cereal lasted through at least three different promotional giveaways.
One of the giveaways was a plastic rocket toy that could be assembled and shot at whomever, but more desirable were sets of four die-cast "micro figures". One was a set of stickers/trading cards, and another were cardboard cutout masks on the boxbacks. I remember getting the Luke Skywalker, but there were other characters available as well. Six in total.