[tomp]

> Putting down money and expecting to get less money back is irrational, unless you're rationally pursuing some higher goal

Actually, economists assume that most people are not pursuing to maximize money, but to maximize their utility function instead. Granted, they also assume that most people are risk-averse as opposed to risk-loving, i.e. most would not risk 1 for a 50% chance of winning 2.0001. On the other hand, the economics of the lottery are such that the amount you pay (even if you play every day for your whole life) is quite negligible compared to all the money you will earn during your life; if you win, you will practically maximize the utility of a few very important things in life (earning more, and working less). I think it's rational to play the lottery.

[kazagistar]

From everything I see, money does not scale all that well with happiness. Thus, those dollars you spend now are almost certainly going to be more valuable to you (buck for buck) then the dollars you have when you are rich. So its not just the chance that is low, but the payoff is even lower.