Kuji is the japanese word for lottery. In Japan (where most kuji orignate from), it is a form of sure-win lottery where there are prizes you can win for each ticket. Each kuji typically have 60 - 80 prizes to be won in a single set.
Every kuji set have different variety of prizes usually categorise from A-Z prize. Prizes can range from small to big, figurines, posters, original illustrations, towels, cups and other merchandises related to the theme of the kuji set.
Apart from A-Z prize, there is Last One Prize and Double Chance Prize.
BANDAI's Ichibankuji (一番くじ) made up most of the current kujis available in the market. There are also other kuji released by Sanrio, SEGA etc.