badge item
n. A piece of clothing or other item that a person wears or consumes to make a statement about their taste or personality.
Examples
2001
Michael C. Bellas, chairman of Beverage Marketing, suggested the new ads hit "the sweet spot for imports, co-ed social occasions. Beer has become very much a badge item," he added, "it makes a statement about the beer drinker."
—Jane L. Levere, “Foster's beer is putting a new twist on its longtime 'How to speak Australian' campaign,” The New York Times, March 06, 2001
1991 (earliest)
If Zollo's research tended to demolish some ancient myths about teenagers, it reinforced a great many others, especially those that centered on their more materialistic instincts. "We learned that skippies are not that dissimilar from yuppies in what's important to them," Zollo noted. "That includes money and badge items that tell their peers how they wish to be perceived, such as the brand of jeans they buy, athletic shoes and obviously cars."
—John Blades, “Hep to what's hip,” Chicago Tribune, February 18, 1991