Causes of the Great Depression

INCOME
The roaring twenties are over and so is the prosperity that came along with it. We were doing so well. Everyone seemed do be doing so well. I thought it would last, but I was wrong. The money I make is no longer able to feed my family. I don't know what to do. In the newspaper I see these articles about the rich and all they talk about is how the rich need to do more for people like me. It's not a new argument. Before I didn't really care. I was doing fine. My family was doing fine. No need for some rich guy to fund public works in my community or anything like that. But now I see what they were talking about. The gap they always mentioned and how the rich need to help close it by giving back with their money. This uneven distribution of money needs to change. How is it fair that the top percent of the richest Americans receive over percent of all income and I constantly struggle to make ends meet and help my parents put food on the table for my sisters. I just don't get it.
- Mary Anne Smith

In the 1930s, there was an uneven distribution of income due to the drop in consumer demand. As people stopped wanting cars and refrigerators (because they already had them; don't really need two), production in factory's also fell. And with the drop in production came a rise in unemployment. This made the income gap increase.

https://www.reddit.com/r/PoliticalHumor/comments/1aohds/an_old_political_cartoon_from_the_1930s_more/
The political cartoon to the left show the vast gap not only between the wealthy and poor but the wealthy and the "common man".