What does margin have to do with it? Why is using the money efficiently important? What is your definition of efficiency? Lets assume he is dirt poor, rather t

What does margin have to do with it? Why is using the money efficiently important? What is your definition of efficiency? Lets assume he is dirt poor, rather than broke. Everyone needs food and groceries. If he spends the food-stamps on food, he will likely spend the money that he would have spent on groceries on something else. By giving food stamps, you've given him a surplus of money, so he'll buy something that he needs but can do without, or a luxury good that he wants. Lets assume now he is rich. We give him a tax break equivalent to the food-stamps (or even the same food stamps). He's already buying everything he wants and putting some in the bank. With the food stamps, he is able to put more in the bank. If the money is in the bank, it can be loaned to the poor guy, but it is actually (eventually) taking money out of the economy when it is loaned... the poor guy has to eventually pay it back to the bank with a few % interest.... it isn't actually getting 'spent' on anything.