Charles Dickens both wrote his novel and set his novel in Victorian England (the middle of the nineteenth century), a time when there was a great disparity between the rich and the poor in England; therefore, the way people lived reflected either great wealth or extreme poverty. England was becoming an industrialist nation, and there was a grand amount of money to be made for those who were already blessed with wealth. It was the poor of the time, however, who suffered greatly. They often worked unbelievable long hours for very little pay doing repetitive and menial jobs, including the children!
In contrast, on the countryside it was the ownership of land that mattered the most. Someone who didn't own land was destined for poverty. At best, the poor people could only hope to move to the city in order to seek their fortunes. Many who failed to achieve the success of their dreams, both young and old, would turn to a life of crime on the streets. Similarly, those who did have money often used it to leave London in search of a more genteel existence.
The time that Charles Dickens (1812 - 1870) describes in Great Expectations is the early half of the 19th century in Britain. This was the time that the British Empire, under Queen Victoria, began to expand and eventually dominate the world politically and economically by the latter half of the 19th century. The stupendous growth was a result of Britain fully transforming from an agricultural to an industrial economy, the first in the world to do so. This transition caused much dislocation, and strained the old social order, as the rich became very wealthy, the poor became middle class, and large numbers of people who wouldn't have been able to live in 1750 now were at least alive, but very poor. By 1850, London was the world's most populous city, as people from the countryside came to seek jobs, causing the crowded and unsanitary conditions Dickens describes in other of his stories. The population of poor seems to have peaked between 1830 and 1850. The reasons for the crowded and poor conditions stem from industrialization--Britain became a victim for a generation or two of its own success--having industrialized, the standard of living rose, allowing the population to increase, but neither the old agrarian nor new industrial labor could absorb all the sudden population increase. Having no chance to support oneself in the countryside, the "surplus population" moved en masse to the city. Thankfully, after 1850, improvements had come about in sanitation, housing, mass transit, as well as the development of even newer industries that continued to raise the standard of living. A middle class continued to grow and thrive, rather than masses of destitute just barely (or not!) surviving, as they were in the early 1800's. The story concerns itself with the travels of Pip, from the countryside to the city, but with an important difference between what is depicted in the novel and the general movement in the society of the day -- Pip doesn't "go to town" to seek his fortune, he's already in possession of financial resources; and the novel explores "what it means to be a gentleman."