Wimpy-nomics
It recently struck me that one of the finest examples of the time value of money is expressed by Popeye's friend Wimpy: "I will gladly pay you Tuesday for a hamburger today."
Of course he'll be glad to pay because the cost of a hamburger in today's money is worth more than the money, ostensibly the same amount, he'll be paying back on Tuesday.
My advice: Buy him a hamburger but charge him interest.