In depressed economic conditions, if you're poor, you will do almost anything to get your hands on more money, because you need it to live. The "value of money" in terms of purchasing power has gone down, but the "value of money" in terms of what you will do to get some has gone up — that disconnect is the "paradox".
Under the same conditions, if you're Caesar, you will be free with your money. There may not be much to buy outright, but by giving money away (or giving loans at generous terms) you can improve your public image, and make a lot of people indebted to you, "more cheaply" than at any other time.
I'm not enough of a historian to reference any real-life examples, but the play makes the point over and over of Caesar getting ahead by his magnanimity — that he gets more by giving freely than by taking.