The most notable instances of cultural reflection in Pride and Prejudice have to do with the way society at that time was delineated by lineage, ranking, fortune, and class. The lower end of that spectrum, to which the Bennet family belonged, was at the mercy of the upper classes: They were meant to respect them, accept their attitudes, understand their moods and attend to their needs at all possible.
Then there is the aspect of marriage. In P&P the problem with not being married is that women had no rights to property, rank, or even respect if she were a spinster, since she would end up inevitably becoming a problem for someone in the family who would need to keep her under their roof.
Respectability, hence came in the form of social status, marital status, financial freedom, aristocratic title, and on the can Do's of a family. The actual value of good and honest behavior, a simple lifestyle, and the commodity of simplicity were underrated as "common" and set aside.
The society of Pride and Prejudice is that of England at the start of the 19th century. In this society, class distinction and wealth were of primary concern amoung the upper classes, and because women were financially vulnerable, their best chance for a comfortable life was to marry well (at least well enough). Most of the plot of Pride and Prejudice is a reflection of this cultural setting.
Mrs. Bennet is obsessed with finding suitable, and preferably wealthy, husbands for her daughters. If none of the girls marries well, the girls will be financially destitute upon the death of their father. None of the girls can inherit his estate due to an entailment, so they will be left to live on next to nothing unless at least one of the girls can marry a man of means. While her behavior and attitude are satirized, Jane Austen is also satirizing the social structure of England that creates this situation for women. With that in mind, Mr. Bingley, Mr. Darcy, Mr. Collins, and Mr. Wickham all represent some part of that social culture.
Mr. Bingley is wealthy enough to provide for Jane, and could also help any of the other unmarried sisters. Mr. Collins will inherit the Bennet estate, so a marriage to one of the daughters would ensure a stable future for all the girls, which is why Mrs. Bennet is so distraught when Liz turns him down. It is also while Charlotte agrees to marry him -- not for love, but for financial security. Mr. Wickham's affections change through the story because he is not a man of wealth and is seeking a women of means. He only marries Lydia when the financial incentives come through Mr. Darcy.
Socieity's concern over wealth and status affect the behavior of some characters in the novel. People of the aristoracy such as Mr Darcy and Lady Catherine felt a need to consider their social status when choosing their spouses. Darcy, in his failed proposal to Elizabeth, speaks specifically about the fact that she is not of the right class, but he loves her enough to marry her anyway. Not exactly the right thing to say to the woman you love, but it serves to highlight the culture at the time. Lady Catherine's trying to manipulate a marriage between her daughter and Mr. Darcy is more of the same idea. The upper classes sought to maintain themselves through marriage within their own social circles.