There are several formats of lottery. The prize can be in cash or in goods. If the organizer doesn't sell enough tickets, he takes a big risk. The prize can be also a fixed percentage of the receipts. The 50-50 is very popular, where the organizers promise that the prize will be 50% of the revenue. The prize can be guaranteed to be unique since each ticket has a unique number. Many lotteries allow the players to select the numbers on the lottery ticket resulting in the possibility of multiple winners.

Usually, the lotteries are run by the governments and are sometimes described as a regressive tax, because the ones more likely to buy tickets are the less affluent members of society. Lotteries are seen as the governmental revenue-raising mechanism that attract those consumers who don't see that the game is a very bad deal. The lottery tickets have to be worth a lot less than they cost to buy, therefore the organizers assure their profit.

The fact that lotteries are commonly played leads to some contradictions against standard models economic rationality. However, the purpose of some players may not be to win the game, but just to have a thrill and indulge in a fantasy of possibly becoming rich. This is particularly popular among those who believe their chances of becoming rich are already zero, so even if the lottery's odds are awful, they are better than zero.