Economists often puzzle about why people, in particular poor people, buy so many lottery tickets. Think about it, we generally consider that people are averse to risk, and lotteries certainly do not reward risk, as a substantial part revenues are essentially taxed away. So why do people buy lottery tickets?
John Laitner argues that this is because of the means tests poor people face: buying a lottery ticket will not make them any poorer as they will still stay eligible for social assistance. If they win, however, they can escape poverty for good. Thus, they win in expected terms. In a sense it is about the dream of escaping poverty, and it is close to free.
John Morgan argues that lotteries, as long as they help in providing a public good, can replace efficiently taxation. Lotteries work better that voluntary contributions. John Morgan and Martin Sefton confirm this in a laboratory environment. Rob Moir, also in experiments, shows that this reasoning may collapse if there other public goods to be financed.
Bruyneel, Dewitte, Franses and Dekimpe try to show that people play lottery more when depressed, say, because of reduced sunlight. Thus lottery is fun, especially when life is not fun.
But I do not think economists can be convinced of buying lottery tickets yet...