I need information about "old money" and "new money" as described in The Great Gatsby and in 1920s American in general.
The first link will give you information of the period altogether. That will help answer your question a little more completely. But the old rich were conservative people who were used to the wealth and success. Most of them stayed in the west, as not to run into the "new rich" in the east. The bigger cities were in the east, so this is why they were labeled such.
After World War I, women became liberated because of their role in the work force when the men left for war. Once the men came back, women were definitely more outspoken and styles began to change (skirts got shorter)--flapper style, as did their hairstyles. Long gone were the long locks of feminine hairstyles. Many women went with a shorter look.
So all of these changes were going on in the big cities. Those who stayed in the west stayed conservative, while the Roaring 20s continued on recklessly in the east (big cities). The new rich became so materialistic with their new found wealth that they spent without thinking and cared for themselves only. They were not afraid to do something at the expense of another person. This is what separated the old money from the new money. The new money became embarrassing to the old money, which is why they tended to stay where they were and not move to the larger cities.