The film has to do with "economics" in the sense that it tells the "rags to riches" story of a man who loses everything on a bad investment but earns his way into a successful career as a broker through determination and hard work. It also provides a window into how Wall Street firms operate and how deals are made. I find that the film is more concerned with the social or psychological costs of capitalism, however, than the actual workings of the economy. Will Smith's character is a great salesman and someone who has a great deal of personal integrity, yet a series of bad choices, fueled in part by his enthusiasm for "making his fortune," and in part by his desire to provide for his family and gain social status, causes him to become homeless. Even though Smith experiences first hand the brutality of the capitalist system in the US, and is reduced to living in a subway men's room with his son, he nevertheless sees the chance to compete for a job in a stock trading firm as his way out.
The film is very clear about the costs of pursuing this dream, both for Smith and his son (Smith's real life son Jaden was cast as his fictional son in the film). In a way, it is his need to provide for his son and set an example that drives Smith to win the competition for the job. Although the "system" has real impacts on his son's state of mind, Smith is determined to show his son that his father can be a "winner" and that hard work and believing in your dreams will pay off in the end. In this sense the film is optimistic about American capitalism; this story of the film is a kind of recapitulation of what "market economies" are supposed to enable: the ascendance of the "best" products through intense competition.
I think that the film relates to economics in a couple of ways. The first is that Gardner is depicted as wanting to succeed in an economic condition that is also making his life difficult. Gardner seeks to find success in a capitalist configuration. Yet, it is this same configuration that contributes to making his son and himself homeless. Gardner's desire to find economic success in the economic condition that is making his life a challenge represents a unique perspective on economics. At the same time, Gardner's internship is shown to be in the very intense and brutal world of capitalism. Gardner is further shown trying to teach his son the lessons of survival in the world is one that does not have to trade off with being a compassionate human being. In this light, Gardner is teaching or parenting in a realm that understands the economic condition in which they live, but does not absorb it. Gardner does not teach his son some type of Social Darwinism, but rather teaches him how he needs to assert his own sense of self without trading off with others. It is here where I think that economics is present in the film and creates a unique dynamic in terms of assessing what is and what should be.