In the Novel, Jay Gatsby is represented as new money. Jay had been making his profit selling alcohol illegally. He earns his money very quickly and throws big parties to show off his money and luxury's. Since Jay is receiving his money from a new source and being illegal. Jay resp resents the new way to make money and become successful
While Tom Buchanan represents old money and the traditional way to make a hard earned dollar. While Jay is making a profit from something illegal while Tom is making a profit the old way, through sweat and hard work.
However both characters are both following their dreams. Jay's dream is to become very wealthy after spending time with the wealthy Dan Cody. While Tom is leading a wealthy life with his profession. Both characters represent money but Jay is one of being illegal.