The play is called The Miser, so you know that money is going to be its number one symbol. In fact, you can size up just about any character in this play based on their attitude toward money. Harpagon, for example, seems to live for nothing other than hoarding money. Even when he's presented with the opportunity to marry a beautiful young woman, his biggest concern is that "There's just one little difficulty. I'm afraid she might not bring as much money with her as could be wished" (1.4.55). Apparently, the guy values money even more than having someone to grow old with (or even having a trophy wife).
Even when Harpagon thinks of celebration, he tends to only see it in terms of dollars and cents. But even someone as miserly as him knows that on some level, it's appropriate to spend some money on special occasions. That's why he makes the huge sacrifice of having a dinner for ten guests. When told what he'll need to buy for the feast preparation, though, Harpagon's immediate response is, "Good God, that's enough to feed a whole town!" (3.1.41). Even in situations where it's appropriate to feed others, Harpagon thinks of money before he thinks of a basic human function like needing to eat.
Harpagon nearly falls in love with his servant Valère for saying, "'You should eat to live, not live to eat!'" (3.1.48). In other words, Harpagon is willing to reduce life to its sparest, dullest most basic form if it means saving a little money. He even asks Valère to return any uneaten food to the caterers to see if he can get a refund on it. Harpagon's greed is taken to ridiculous extremes when it's brought into contact with something like food, since food is a basic human need. You have to spend money on food, whether you like it or not.
In contrast to Harpagon, his son Cléante thinks that money is only good when it's being spent. He also believes that money is wasted on old people like Harpagon, as he wonders out loud, "What use will money be to us if it comes only when we are too old to enjoy it?" (1.2.17). In other words, Cléante believes that a dollar spent by a young man is better than ten dollars spent in old age. This seems to be the view of Anselme as well, as he brings the play to a happy conclusion by showing himself willing to part with his money in order to bring happiness to others.