Thrift shopping used to carry a certain stigma, but Gen Z didn't get that memo. They're leading a secondhand clothing boom that's pulling in older generations too, driven partly by inflation and tariffs making new clothes feel like a luxury purchase. What started as a budget-friendly alternative has evolved into something bigger: a legitimate business opportunity that's reshaping how Americans think about their wardrobes.

A Two-Sided Marketplace Taking Off

The demand for used clothing has created an entire ecosystem of resellers who hunt for bargains and flip them on platforms like eBay (EBAY). These middlemen are capitalizing on strong buyer interest, and the momentum shows no signs of slowing down since younger shoppers are driving the trend forward.

Here's the interesting part: buyers don't see thrift clothing as settling for less. They see it as smart shopping, a way to snag quality items at a fraction of retail prices. In many cases, they're finding clothing that's actually more durable than what's on department store racks today.

"The stigma around secondhand clothes really died with the baby boomer generation," William Blair & Company Research Analyst Dylan Carden told CNBC.

The Numbers Tell A Growth Story

ThredUp (TDUP) put out its 13th Resale Report, and the projections are pretty remarkable. The global secondhand apparel market is expected to hit $367 million by 2030, while the U.S. market alone should reach $74 billion by 2029.

ThredUp is riding this wave hard. The company's revenue climbed 34% year-over-year in Q3, helping push its stock up more than 400% year-to-date. That's a dramatic turnaround after years of sluggish performance, suggesting that both investors and shoppers are finally waking up to what's happening in this space.

The company now has 1.57 million active buyers, and new buyer growth hit a record 54% year-over-year. Management says the most recent quarter was the best they've ever seen for new customer acquisition. That kind of growth doesn't happen by accident.

Inflation and tariffs are helping secondhand clothing grab market share from traditional retailers. People want to stretch their budgets, and buying used clothing feels less wasteful than constantly buying new stuff. Sustainability matters to younger shoppers, and thrift shopping checks that box while saving money.

AI Is Changing The Game

Artificial intelligence is making its way into thrift shopping, and it's solving real problems. Sellers can list items faster, and buyers can find exactly what they're looking for without scrolling through thousands of listings. It's removing friction from a process that used to require serious time and patience.

"AI has the potential to really transform the way that people are shopping online right now," Scalable co-founder and Co-CEO Jasmine Enberg told CNBC.

Shoppers can now type in a single prompt and get personalized recommendations. Less time searching means more time buying, which should help the industry grow even faster.

ThredUp CEO James Reinhart pointed out another advantage his company has: everything happens domestically. They receive secondhand clothing in the U.S. and handle all logistics within the country, which means tariffs don't touch their business model.

"We receive more than 100,000 pieces of clothing every day, so it's a business operating at some significant scale," he said.

That's a lot of clothing changing hands, and it's all happening while traditional retail faces headwinds. The thrift shopping trend isn't just a fad anymore. It's becoming how a generation shops, and the rest of America is starting to catch on.