Since The Canterbury Tales are set in a time of economic transition for medieval society, money and wealth play a very big role here, particularly in the portraits of the pilgrims. We see the things money can buy in the descriptions of the clothes people are wearing, the horses they're on, and the gadgets they've got. And we learn about the ways people can make money in portraits of characters like the Merchant, the Tradesmen, or the Wife of Bath. We also hear a lot about the way characters can steal or cheat their way to money, as the Reeve or Pardoner do. In many of the portraits, we witness the way that skill with money-handling can lead to power, deserved or otherwise, and the way lack of concern for money (the Clerk) can be just as troubling as excessive greed (almost all the other characters). Most often, when the Tales talk about money, it's to question the ethics of a particular character's relationship to it, particularly in the case of the religious characters who have taken vows of poverty.
In The Canterbury Tales, facility with money-handling is an important way in which lower-class pilgrims demonstrate and gain power over their masters.
In The Canterbury Tales, the choices a pilgrim makes about how to use his wealth reveal important information about his character.