are peddling bonds on Wall Street, Dexter's investing in a laundry business. Before long, the business takes off, and Dexter starts making some serious money. So although Dexter may appear dissatisfied with his social status, ironically it's served him in good stead. Starting out middle-class provided him with the solid work ethic that's helped him to achieve success in business.

We learn that Dexter's family is not old money. His father owns only the "second best" grocery store in a small resort town in Minnesota—and it is not the grocery the rich people patronize. We learn that Dexter's mother is a lower-class Eastern European (Czech) immigrant, which at least suggests that his father comes from a similar background:

His mother’s name had been Krimslich. She was a Bohemian of the peasant class and she had talked broken English to the end of her days. 

Dexter may not absolutely need the $30 a month he earns as a caddy, but when he decides to quit:

The enormity of his decision frightened him. He was a favorite caddy, and the thirty dollars a month he earned through the summer were not to be made elsewhere around the lake.

His father is prosperous enough to send him to the state university, but Dexter goes to the more expensive prestigious East Coast school. How he pays the difference, we don't know, but we later learn he couldn't afford to go to prom while he was there. After he graduates, Dexter needs a loan to get started and makes his money in a less-than-elite way:

Dexter borrowed a thousand dollars on his college degree and his confident mouth, and bought a partnership in a laundry.

Dexter does very well financially, but is always conscious that his class background—the child of middle-class immigrants with no social connections—puts him at a disadvantage in his new life. He realizes he can't, for example, be careless about what he wears—but he knows his children, growing up with money, will be able to. Dexter is a self-made man who always carries a sense that he does not quite belong in the world of the wealthy. 

In the very first paragraph of F. Scott Fitzgerald's short story "Winter Dreams," the third person narrator indicates that Dexter Green's father "owned the second best grocery store in Black Bear—the best one was the 'Hub' patronized by wealthy people from Sherry Island—and Dexter caddied only for pocket money." This snippet of information seems to reveal that Dexter comes from a middle class family but that the narrator, and Dexter himself, are keenly aware of the upper class.

Dexter comes from comfortable circumstances. His father, who is revealed at one point as "prospering now," offers to pay for Dexter's education at a state college, but Dexter strives for something else and attends a "more famous university in the east" (possibly Princeton, where Fitzgerald attended) where he is plagued by "scanty funds." Dexter has an obvious fascination for the rich and wants to become one of them. He directly parallels another Fitzgerald character, Jay Gatsby, who buys a giant mansion on West Egg (a symbol for the new rich) across from East Egg (established wealth). Dexter, too, becomes quite wealthy in the laundry business and eventually moves to New York. Like Gatsby, Dexter falls for a selfish and willful girl, Judy Jones (a forerunner of Daisy Buchanan), who comes from established wealth. And, just like Gatsby, Dexter is rejected in the end.