Not unlike Charles Dickens, Charlotte Bronte exposes one of the social institutions of the age and its ill treatment of the orphaned. Her father, Patrick Bronte, was an Anglican minister and of a most charitable spirit that, too, concerned itself with the poor and needy. So, it is certainly understandable that she should convey the plight of the poor in the character of Jane Eyre.
I have to support the other posters here. Jane, while she should have been taken care of, was forced to live in horrible conditions. After leaving Thornfield, she must find anyway she can to survive. For Jane, nothing is beneath her at this point in her life. Her poverty has overtaken her.
Of course, Jane herself experiences poverty at various stages during this excellent novel. The most notable sections are when she is sent to school at Lowood and experiences the terrible living conditions there, including very poor quality food and also cold and exposure to disease. The second time she experiences poverty is when she flees Thornfield Hall after her abortive marriage day and is forced to beg.
One very significant aspect of the portrayal of poverty in Jane Eyre is that Mr. Brocklehurst, a nominal Christian, is presented as a person who benefits from exploiting others. In this respect, Jane Eyre resembles some of the poetry of William Blake, who also sometimes showed how hypocritical Christians benefitted from the poverty of others. Of course, both Blake and Bronte admired people who genuinely lived their Christian faith.
In Jane Eyre, we see poverty in several instances. Because Jane is an orphan, she is taken in by her Aunt Reed because her late husband made her promise. She is treated like a poor relation (which she is) and is physically abused by her cousin John and emotionally abused by her aunt.
When Jane is sent away to Lowood School, there is no money there—the girls are all orphans with nowhere else to go; the school is supported by wealthy members of society, but the school is poorly run by Mr. Brocklehurst. The food is meager and often burned; the water is frozen and the girls have very little. It is safe to say that Helen dies in good part because of the terrible conditions.
Of course, in both of these places, there is also spiritual, moral and ethical poverty. Mrs. Reed hates and resents Jane, and Mr. Brocklehurst talks about God and redemption, but he is hateful. There is symbolic poverty and literal poverty in the story.
The novel, like many novels of this time period, conveys the dire straights that women would be in if they were unable to marry and be supported by a man of means. Jane has to make the best of her situation, and a fine heroine she makes, but the underlying theme of the place of women in society is not to be ignored. It is clear in the novel that her job as governess is the only thing that will provide for her most basic needs.