A candy toy is a toy that comes with candy, sort of like a fast-food promotional toy but not. They basically only make them in Japan, where this is done primarily to sell small, inexpensive toys without the standard taxes applied, since they are technically food items (for a given value of "food", since nine out of ten times we're talking "tasteless white sugar pellets" or "plank of rock-hard flavorless gum-like substance") and therefore get sold tax-free.
Kabaya is the primary maker of candy toys for the Transformers brand in Japan. Generally speaking, they consist of scaled-down model kits or limited-possibility action figures of various characters. (It is worth noting, however, that candy-toy models exist of Rumble and Ravage that are actually larger than the original toys!)
There are candy toys dating back to various Generation One lines, even up through Beast Wars and the Unicron Trilogy. During Micron Legend and Galaxy Force, the boxes often had individual Mini-Cons that were largely similar to the existing normal-retail toys, but were in actuality all-new molds based on the Takara-made toys; close inspection reveals minor mold differences, and sometimes they were cast in different colors of plastic.