I don't entirely agree with linda-allen, I am afraid. Whilst she is completely right about the central focus on marriage in a world where the only way of gaining some measure of independence for women was to marry (just look at how desperate Charlotte Lucas is to marry - she'll even have Mr. Collins!), I don't agree that property and intrigue are the central motivations for all the characters. Certainly, for some marriage-obsessed individuals (like Mrs. Bennet) it is all about marrying off her daughters, and she devises stratagems such as forcing Jane to ride to Netherfield to make sure she stays the night, to accomplish that purpose. But if you feel that property and intrigue are at the heart of every characters' motivation you are slightly cynical! If this was the case, Lizzie wouldn't have made enemies with Darcy so rapidly. And can we accuse Jane, sweet lovely Jane, of intrigue in trying to get Bingley to marry her? So this statement is true of some characters, but certainly not of all.
Yes, I agree that marriage, property ownership, and romantic intrigue are what Pride and Prejudice are all about. The Bennetts have 5 daughters. In Regency England, if a woman did not marry well, meaning to a wealthy man, her life would be hard. In the movie "Becoming Jane," in which we see Jane Austen begin to write Pride and Prejudice, when Jane turns down a proposal because she will only marry a man she is attracted to, her mother says, "Attraction is desirable; money is indispensable."
One reason why Mrs. Bennett worries so much about her daughters is because the law prohibited females from inheriting property from their fathers. The Bennett home will go to Mr. Collins instead of to one of the daughters. Remember that he first wanted to marry Jane, but Mrs. Bennett persuaded him to propose to Lizzy. He ended up marrying someone else. So Mrs. Bennett is terrified that they'll end up homeless.
When Lydia elopes, the scandal is not that she is so young or that she has married before her older sisters. In those days, a couple could go to Gretna Green in Scotland and needed just two witnesses to say they were married--no church service was needed. Elopement brought disgrace on the whole family because no "decent" person would accept that kind of marriage.
As for intrigue, Mr. Wickham is the very image of deception. He tried to extort money from Mr. Darcy, and he had no intention of marrying Lydia.