One of the major themes of Jane Austen's Pride and Prejudice is that of wealth and social class.
Note that the Industrial Revolution plays a large role in shaping the society in which Austen sets the story. For many years there had been a wide separation between the poor and upper-class; the advent of wealth earned through trade created a strong middle-class in England. People, for example, who raised sheep, were able to earn money through trading English wool which was preferred over wool from the Continent. English wool became desirable in other countries, and the sheep farmer became a wealthy member of the emerging middle-class. Still dismissed by the aristocratic element of society—for his rough manners and his "new" money, the middle-class merchants also became objects of resentment in that they often possessed more money than many members of the aristocracy—who lived "large" and spent money that was not easily replaced.
It becomes evident early on that wealth and station have a great deal of bearing on Austen's presentations of certain characters. Lizzy (our protagonist) is from a family of the middle-class gentry. Their money comes from work, not from "old money" passed down through one's family.
The central theme of Pride and Prejudice has to do with the Bennett family having five daughters. The members of the family are of the class of "gentry", meaning that it would be a violation of class norms for them to actually work in order to earn money; instead, they live on inherited wealth. There are two ensuing economic problems.
First, Mr. Bennett having no living son, his estate devolves on Mr. Collins, leaving nothing capable of supporting his daughters after he dies (although he is in healthy middle age in the novel, obviously his daughters will be likely to survive him). Since his daughters have no means of being self-supporting, they must make good marriages to continue to live as gentlewomen.
Unfortunately, the dowries of the daughters are small and...