F. Scott Fitgerald's The Great Gatsby is narrated by Nick Carraway; it is through his eyes that we see and know the other characters, including Jay Gatsby. Nick's understanding about Gatsby and his money is different at the end of the novel than it is in the beginning; as he comes to know Gatsby, Nick understands how Gatsby really feels about (and uses) money.
Nick lives in a little house (that is actually too grand a term) dwarfed by his neighbor's glistening mansion. Gatsby throws lavish parties and spends his money quite extravagantly. When the two men finally meet, Gatsby takes great pains to try to impress Nick with his past and his wealth.
I lived like a young rajah in all the capitals of Europe--Paris, Venice, Rome--collecting jewels, chiefly rubies, hunting big game, painting a little, things for myself only....
Nick should have known there is more to the outrageous story, because Gatsby adds this:
...and trying to forget something very sad that had happened to me long ago.
When he wants to ask Nick a simple favor, Gatsby does not have the social skills to just ask, so he offers Nick an opportunity to make more money--the only thing he has to offer anyone but Daisy, it seems. Nick is appalled at the idea and neither of them mentions it again.
Later Nick learns that Gatsby was unable to marry the woman he loved, Daisy, because he was not rich enough to suit her parents. He dedicated his life to making money and throwing elaborate parties because he hoped Daisy would one day attend one of them. She has not, so now he asks Nick to invite Daisy (his "careless"cousin) for tea. Nick says:
The modesty of the demand shook me. He had waited five years and bought a mansion where he dispensed starlight to casual moths--so that he could come over some afternoon to a stranger's garden.
Nick claims a personal disdain for money from the beginning (though he is a stockbroker whose aim it is, presumably, to make a lot of it), and he does not admire Gatsby at first because he seems to be so ostentatious with his. As he learns why money is important to Gatsby and why he throws such lavish parties, Nick understands Gatsby's hunger for money.