The Size of the Opportunity
If you’ve scrolled through Depop, Poshmark, or even Instagram’s Reels lately (where a thrifted Coogi sweater is trending again), you’ve probably noticed a recurring theme: “Sustainable fashion” is everywhere. But this isn’t just a buzzword—it’s a goldmine for resellers who know how to play the game right.
The numbers don’t lie: The global sustainable fashion market was worth $7 billion in 2023 and is projected to hit $13.5 billion by 2031, growing at an 8.58% annual rate. Meanwhile, the secondhand apparel market is expected to balloon to $350 billion by 2028—far outpacing the growth of fast fashion. (renewtiful.com) And here’s the kicker: 60% of consumers are willing to pay more for sustainable fashion. (wifitalents.com)
For resellers? This is the equivalent of walking into a store where everyone’s already holding their credit cards out. But like any gold rush, timing is everything. By 2025, competition in the resale arena will spike, especially as platforms like Depop double down on tech upgrades and brands lean into “green” marketing. The question isn’t whether sustainable fashion is a trend—it’s how resellers can harness its momentum before the market becomes oversaturated. Let’s break it down.
Why the Boom in Sustainable Fashion?
Let’s start with the “why” before diving into the “how.” The rise of sustainable fashion isn’t just about environmental guilt. It’s a cultural shift driven by three factors: cost, convenience, and conscious consumerism.
- Cost: Fast fashion is getting pricier. Inflation has hit Zara harder than kombucha sales—so shoppers are ditching shipping fees for thrifting apps.
- Convenience: A Depop purchase lands faster than a 7-day Amazon delivery. And with 90% of Depop’s 30 million active users under 26 (time.com), Gen Z is trading their Venmo codes for vintage Dior goggles.
- Conscious consumerism: People care. A 2024 Deloitte survey found that 75% of Gen Z consider sustainability before buying. And guess what? They live online. Which means if your listing on Vinted doesn’t scream “eco-friendly,” you’re losing clicks.
But here’s where it gets spicy: sustainable fashion isn’t just patagonia puffers and thrifted Levi’s. It’s also upcycled jeans with neon stitching, DIY tie-dye tees, and deadstock fabric transformed into capsule collections. The market is hungry for innovation—and resellers who tap into niche subcultures (vintage skatewear, sustainable lingerie, etc.) can pull in higher profit margins.
Mastering the Platforms: Depop, Poshmark, and Beyond
Let’s break down the biggest resale players and what they offer.
Depop: The Gen Z Marketplace
If you’re new to Depop, think of it like eBay… if eBay had TikTok vibes and a 9pm Influencer sale every Tuesday. With 90% of its 30 million users in the 13–26 age range (time.com), this is where the “quiet luxury” trend started and where teenagers will fight to death over a Y2K Juicy Couture tracksuit.
- Pro Tip #1: Use keyword-optimized titles. Depop’s algorithm loves searchable terms like “Vintage 2000s polka dot dress,” “Stella McCartney vegan leather bag,” or “Patagonia organic cotton hoodie.” Ranking high in searches = more clicks = faster sales.
- Pro Tip #2: Storytelling sells. One Depop seller, Emily R., made $3,000 last month selling hand-repaired vintage denim. Her secret? On each listing, she wrote a 3-sentence “before/after” story: These jeans were found at a thrift store in Austin, Texas. Minor holes patched with red stitching to turn them into a statement piece. Buyers ate it up.
Poshmark + Mercari: The Reliable Workhorses
Poshmark and Mercari might not trend on TikTok, but they’re where your parents’ closet donations end up—and in 2025, that’s a goldmine. Older audiences (30–60) shop here religiously for brands like Talbots, Lululemon, and Lands’ End.
- Pro Tip #3: Nail the listing photos. Poshmark users judge you based on your first photo. Invest in a ring light and shoot the garment laid flat. No blurred lighting, no clutter.
- Pro Tip #4: Bundle deals. Poshmark’s “Make an Offer” feature works like a charm. Try listing a matching Jean Jacket + Skirt set for $50 “or OBO.” Buyers love deals, and bundling increases profit margins.
How to Source Sustainable Fashion Strategically
You’re not going to build a thriving resale business by picking apart your ex’s closet and hardly touching your coffee budget. Reselling is a numbers game, and strategic sourcing is your cheat code.
1. Partner with Local Thrift Shops
Thrift shops get new inventory every day—some of it directly from donations, some from suburban garage sales. Build relationships with employees. A simple “Hey, I’d love to check out the backroom racks” can score you first access to premium donations. One seller in Phoenix, Julien T., runs a $10K/month Instagram resale page by visiting a Goodwill scrape bin every Monday morning before it opens. (Yes, such a thing exists.)
- Scraping walk-through:
- Visit 3 local thrift stores.
- Ask after 4 PM about incoming items.
- Offer to sort boxes for 10–15 minutes in exchange for first access.
- Scan for luxury logos, vintage denim, and niche colors like beige, olive green, or rusty red (trust us—those are trending).
2. Target “Deadstock” Sales at Liquidation Stores
Terminix Liquidation centers, for example, auction off returned, defective, or overstock merchandise—including highly sustainable brands like Reformation, Patagonia, or Allbirds. These items are never sold by Depot users en masse, meaning you get exclusivity.
Red Flag: *Don’t buy bundles if you can’t sort through the lot first.* One reseller came home with 5 bags of liquidation jeans only to discover they were all juniors’ sizes. Learn from them.
3. Scout Instagram Sellers Looking to Exit
You’d be surprised how many small-scale resellers quit after 6 months. They’ll post a sale-to-close sign on their account. These sellers often sell their remaining inventory at extreme discounts—sometimes as little as 10% of their usual rate.
I did this in 2023 with a seller named Jen D., who was leaving thrift flipping to focus on nursing school. I bought her remaining 15 pieces of Coach-influenced handbags for $200, sold them at $50 each on Depop, and cleared $550 profit in 72 hours.
The Power of Keywords and SEO in Reselling
Selling on online platforms isn’t just about aesthetics or persuasive text anymore; it’s about search engine optimization (SEO). Whether you're on eBay, Etsy, Depop, or Poshmark, keywords are the unsung heroes in putting your listings in front of eyeballs. Think of it like this: you have 1,000 sellers ahead of you on a Google search. If your title is “Gray shirt,” you don’t stand a chance. But if it’s “Vintage 1990s Unisex Oversized Cotton T-Shirt (True Navy Blue, Handwash Only),” you’ve inserted at least five high-performing keywords.
Yes, even resale platforms function like search engines. Depop, for instance, prioritizes listings that match popular search trends. And in 2025? The keyword “sustainable” is ranking in the top 20 phrases searched daily.
How to Plug Into the Trend
Start by using Depop’s search bar and typing any variation of:
- Sustainable women’s shorts
- Secondhand vintage MLB hats
- Upcycled jackets
- Compostable crop tops
You’ll see what thousands of users are searching for right now. Take notes. Try typing long-tail phrases like “best vintage sustainable brands” or “eco-friendly recycled fashion brands.” One seller I spoke with used the keyword “Compostable Yoga Pants” for a Thrive line she posted on Etsy—and got 420 clicks within 48 hours, which led to 17 sales.
Deeper tip: Many resellers ignore their item tags, but they should treat them like metadata. Depop allows up to 10 tags per item. Don’t fill yours with general terms—use 90% keyword-based and 10% vibe (e.g., “Y2K Grunge,” “Festival Inspired”).
Sustainability Isn’t Just Niche—It’s Big Business
If you’ve ever Googled “how can I make more money in resale?” let me answer that with a statistic you should know:
Sustainable fashion brands have seen a 63% increase in consumer interest over the past five years. (wifitalents.com)
That means pre-owned Reformation dresses or outdated stocks of decommissioned Adidas sustainability lines (Adizero pets bottles anyone?) aren’t just “relevant.” They’re hot commodities.
But here’s where resellers often miss an opportunity—they don’t present secondary-sourced fashions as premium lifestyle assets. You don’t want to sell a Ganni animal-print dress as “30% off original.” You want to frame it as a “Rare Blend of Natural Dyes + Vegan Skewering; purchase closes plastic fill loop in local LA.”
Interest in transparency and brand sourcing is at an all-time high. So, resellers who explain the story behind a piece—even if it’s just a paragraph under the photo—can price 15–25% higher and still sell fast.
Overcoming Industry Challenges and Selling “Authentic” Sustainability
Despite the market’s growth, selling sustainable fashion isn’t without its pitfalls. Two challenges loom large: 1) greenwashing, and 2) lack of clear definitions around “sustainability.”
Greenwashing refers to marketers slapping “eco-conscious” labels on products that aren’t any greener than a Hot Topic glitter hoodie. More consumers are getting wise—up to 63% now say they’d avoid a brand that tries this (prnewswire.com).
As a reseller, you’ve got a built-in defense: you’re part of the circular economy already. But to stand out in a sea of others, you need to prove your sustainability claims.
How to Stay Legit
- Verify brands and materials: Use the Good On You app to check certifications. If the brand used in your item has a fair or better rating, mention it in your listing.
- Be specific: Instead of labeling something as “eco-friendly,” say “Made with 80% recycled polyester.”
- Source with intention: Target upcycled, locally sourced, and small or niche designers with clear manufacturing missions.
Last tip? Don’t cheap out on tags or packaging. While recycled poly bags or compostable mailers cost a bit more up front, they contribute to product trust. And trust is currency in the digital marketplace.
Leveraging Social Proof and Emotional Appeal
Let’s get one thing straight: people buy fashion with their emotions, not their logic. And smart resellers use this in their selling tactics.
Case in point: Gabriela Hearst, a renowned designer and advocate for circular fashion, once said, “Fashion needs to shift from a linear to a circular model—take, make, use, recycle—to support the growing global population and limited resources.” (ft.com)
This is the mindset today’s shoppers are tuned into. That’s why resellers who emphasize chain-of-custody stories, climate-forward missions, or movement alignment—like the Degrowth Fashion Movement or Earth Percent—all drive traction.
Simple Mantras to Remember:
- “Buyless. Value More.”
- “Sustainable fashion isn’t a trend—it’s a statement.”
- “Clothing is never finished evolving—your resale can be its next chapter.”
If you’re selling a piece that’s secondhand or handmade, write a short narrative that connects the dots on how your piece contributes to those missions. People don’t just want to wear a shirt or a dress—they want to wear a movement.
Finishing Note: Does It Have Legs in 2025 and Beyond?
As we inch closer to 2025, the answer remains a resounding: Yes. But with increased demand comes increased competition—and platforms like Poshmark and Depop will quickly become saturated.
To stay ahead:
- Double down on transparency, authenticity, and educative storytelling.
- Master your SEO tools.
- Stay on top of shifting keywords driven by evolving consumer behaviors, climate news (think wildfires, oil prices, etc.), and emerging fashion trends.
- Expand your product definitions of sustainability beyond “used” and into upcycled, handmade, fair-trade, slow fashion, etc.
Reselling sustainable fashion isn’t just about making money anymore—it’s about harnessing a global trend and contributing to a much bigger change.
Your first dollar doesn’t come from knowing keywords—it comes from learning how to use them to tell a story. The right story just might be the next bestseller. ...and in 2025? People are ready to listen.
