Social class distinction is precisely what drives the plot, as well as what gives the title to Jane Austen's Pride and Prejudice.
The treatment of the theme begins as early the very beginning of the novel with the words
IT IS A TRUTH universally acknowledged that a single man in possession of a good fortune must be in want of a wife.
This statement is not to be taken without analysis. Historically speaking, the "single man in possession of a good fortune" seldom seeks a wife below his own status. Often, a woman with status but no money may find herself married to a rich man. Yet, to be poor, socially unknown, and married above class is a rarity. Therefore, the wife that this man of good fortuneseeks must meet the latter requirements.
However, in Pride and Prejudice we find that the issues arise more from social standing than from fortune. In fact, the "pride" that identifies Darcy and his circle comes from their sense of class superiority. Even when the Bingleys are not aristocrats, they do have a fortune, but it came from trade. This puts them at a less sophisticated status than Darcy. However, they elevate their class standing by solidifying their networks. Their acquaintance with the likes of Fitzwilliam Darcy, the grandson of an Earl and the nephew of Lady Catherine deBourgh, is surely an asset to their social dossier.
Class also becomes an issue with the lesser titled. These are men who are nowhere near the upper class circle, but who are one small step ahead of the country folk as far as their rank goes.
The first is Sir William Lucas. His knighthood makes him think too highly of himself regardless of the fact that he does not have money to support his rank.
he could think with pleasure of his own importance, and, unshackled by business, occupy himself solely in being civil to all the world.
The second is Mr. Collins, whose parsonage does place him in a leadership position as a vicar. He condescends others simply because he has the patronage of Lady Catherine deBourgh, of whom Collins is a sychophant
Therefore, it is a fact that the lack of money plays a secondary role in the lives of the characters. Class distinction does not neccesarily equate poverty. Most of the pride and the prejudice comes from the need of differentiating one group to another. Remember that even Darcy considered his proposal and potential marriage to Elizabeth as a sacrifice for the woman's lack of social rank. Hence, money is not what concerns Darcy, but the social implications of marrying beneath his class.