In Pride and Prejudice, the opportunities for women lie solely in marrying well, or in Charlotte Lucas's case, marrying at all. Jane Austen highlights this throughout the novel, especially by the fact that the Bennetts will lose their home because it will pass to the next male heir, Mr. Collins, because Mr. Bennett has no son. It is expected that a woman would marry an eligible suitor and possibly be required to take care of sisters that did not marry or a widowed mother. Also, in the absence of brothers in Pride and Prejudice, it is particularly important that the Bennett sisters find wealthy suitors, because their father has made no provisions for them in the event of his sudden death. A woman of this period if she did not marry, might be able to secure a position as a Nanny or Governess. Jane Austen, herself, unmarried, had brothers. She did garner some financial success from her writing but she was never rich. Wife was the best choice for insuring economic security. Otherwise, a life of hardship as a servant in a rich family was the other option and that would be a definite economic deadend.
This novel is set in Regency England, a time when Prince George acted as Regent for his incapacited father, George III. During this time, England was a powerful nation, having defeated Napoleon. The English were strong not only militarily but also economically, with a growing middle class.
Women of any class, however, had very little power socially or economically. In the novel, the Bennett home is "entailed" to Mr. Collins. That means that when Mr. Bennett dies, his estate will go to Mr. Collins instead of to his own daughters because only males could inherit property (see the link to Themes below). Unless the Bennett girls married well, they would end up penniless.
There were jobs for women in lower economic classes, such as domestic service and factory work, but they paid very little. The only option for women in the middle and upper classes was marriage or being a governess:
The only viable alternative to marriage was to become a governess, commonly referred to as the "governess slave-trade" since "minimum wage and hour limitation for workers did not exist at the time." (from Jane Austen and the Female Condition, linked below)
Women are not well-equipped to earn their living during this time period. If born into a working class family, a female would learn young how to do the jobs that are available, basically being a maid. A middle-class family would be able to either produce enough of a dowry that the female children would earn their income through marriage OR the female children would look for jobs as a governess. A girl from a high-class family was expected to marry well. If there was a good dowry to be had, then she could have her pick of men. If there was little or no dowry, then the girl had to rely on her charms to ensure that she is married to a financially solvent husband.
These conditions are shown in the book. Charlotte marries Mr. Collins because he can provide her stability and a home. She can not remain with her parents forever, and she is not equipped (as gentlemen's daughters were not) for employment. Mrs. Bennet tries to marry her daughter off to Bingley because he is rich and that is how a girl earns her fortune. The girls have a father who is wealthy, but because of the fortune will only go to a boy in this family, they are without dowry and so are at the mercy of what offers they get. Wickham does not plan to marry Lydia because she is not rich enough.
In all, women - are particularly high class women - are at the lowest economic rung.