In The Great Gatsby, it took Gatsby three years to accrue the money necessary to buy the house. Gatsby goes about earning this money in ways that are considered less than savory by the upper crust of New York. Although his business dealings are never explicitly explained, we do know that Gatsby was connected with Meyer Wolfsheim. He likely engaged in illegal activities with this shady man, including the sale of liquor during the Prohibition. Tom Buchanan discusses this, claiming:
"I found out what your 'drug-stores' were." He turned to us and spoke rapidly. "He and this Wolfsheim bought up a lot of side-street drug-stores here and in Chicago and sold grain alcohol over the counter. That's one of his little stunts. I picked him for a bootlegger the first time I saw him, and I wasn't far wrong.
Unfortunately for Gatsby, all the money in the world can't buy back Daisy's affections after Tom has exposed him as a criminal.