How does Jay Gatsby flaunt his money in "The Great Gatsby"?
Every night that he has a party, Gatsby flaunts his money. He bought that huge mansion all for himself--that's flaunting his money. The fact that he only throws those parties in hopes of seeing Daisy again is flaunting as well. He never partakes in these parties, he just sits in wait for her to one day appear. All of those preparations just for one girl to impress.
When Daisy comes over to his house (after Nick's where they are reunited once agan) he shows her all of his silk shirts. He has thousands of them in his closet and he continues to toss them down on his bed next to her. He just wants her to know that he has money now. That was all he needed origianally to win her heart. Now he flaunts it by showing her all of the custom shirts he has made.
Gatsby also flaunts it by driving his fancy car and by "correcting" problems that occur at his parties--for instance, one guest had a dress ruined at his party and he sent her a new one. There are many references to gold and silver in his home and in the colors he wears--his suits, his yellow car, his custom made shirts--this is also an effort to show off the extent of his wealth which is all an attempt to win Daisy from Tom.