Every reseller has made at least half of these mistakes. The difference between those who quit after three months and those who build sustainable income is recognizing the patterns early—and fixing them before they drain your time and money.
These aren't theoretical warnings. They're the actual reasons people fail at reselling, drawn from watching hundreds of beginners stumble through the same predictable traps. If you're just getting started with thrift flipping, bookmark this list. You'll thank yourself later.
Mistake #1
Building a Death Pile
The "death pile" is inventory you've purchased but haven't listed. It sits in bags, bins, or that corner of your spare room, slowly becoming dead money. Every unlisted item is cash you can't spend and profit you're not making.
The death pile grows because sourcing feels like the fun part. Hunting for treasure releases dopamine. Photographing, measuring, and writing descriptions does not. But the unsexy work is where money actually gets made.
The Fix: Implement a "one in, one listed" rule. Don't buy new inventory until your current batch is live. For a deeper dive, read how to defeat the death pile.
Mistake #2
Ignoring the Real Math
Beginners often calculate profit as "what I sold it for minus what I paid." That's not profit—that's gross revenue minus cost of goods. Real profit subtracts platform fees (10-20%), shipping costs, packaging supplies, and your time.
An $8 shirt that sells for $25 might feel like a $17 profit. After Poshmark's 20% cut ($5), shipping materials ($1.50), and the 15 minutes you spent prepping and listing it, you've made maybe $10. That's still good—but you need to know the real number.
The Fix: Track every sale in a spreadsheet with actual fees and costs. Know your true profit margin before you celebrate.
Mistake #3
Buying Based on Brand Name Alone
"It's Nike, it'll sell!" No. Nike makes billions of items. Most of them are worth less than the shipping cost. The same applies to Tommy Hilfiger, Calvin Klein, and dozens of other recognizable brands that are massively oversupplied on resale platforms.
What matters isn't the brand—it's the specific item, its condition, current demand, and how many identical listings exist.
The Fix: Check eBay sold listings before you buy. If 500 identical shirts sold for $12 last month, yours probably will too—minus fees and shipping, you're breaking even at best.
Mistake #4
Buying Traps That Never Sell
Some categories are nearly impossible to move profitably: outdated formal wear, generic suits, fast fashion basics, and anything without a specific buyer in mind. These items clog your inventory and tie up capital.
The Fix: Learn the 10 items you should never buy. Having a "do not purchase" list is just as important as your BOLO list.
Mistake #5
Overpricing and Waiting Forever
Pricing based on what you hope to get instead of what the market actually pays leads to stale inventory. That jacket sitting for six months at $85 might have sold in a week at $65—and that $65 could have funded your next three flips.
Time has value. Money sitting in unsold inventory can't be reinvested.
The Fix: Price based on sold listings, not active listings. If something hasn't sold in 30 days, drop the price or re-evaluate whether it's worth holding.
Mistake #6
Terrible Photos
Dark, blurry, or poorly composed photos kill sales. Buyers can't touch the item—photos are everything. A great item with bad photos looks like a bad item.
The Fix: Shoot in natural light near a window. Use a clean, uncluttered background. Take at least 6-8 photos showing the front, back, tags, and any details or flaws. Your phone is fine; the lighting is what matters.
Mistake #7
Skipping Measurements
"Size Large" means different things to different brands—and buyers know it. Skipping measurements leads to returns, which eat into your profits and tank your seller metrics.
The Fix: Measure pit-to-pit, length, and sleeve length for every top. Waist and inseam for every bottom. It takes 30 seconds and prevents problems worth far more than that time.
Mistake #8
Hiding Flaws
Not mentioning a stain or hole isn't clever—it's a guaranteed return request and potential negative feedback. Experienced buyers check photos carefully. They will find the flaw, and they will be annoyed.
The Fix: Photograph and describe every flaw. Honesty builds trust, reduces returns, and often doesn't hurt sales as much as you'd think. Buyers appreciate transparency.
Mistake #9
Single-Platform Selling
Listing only on Poshmark means you're invisible to eBay's 135 million buyers. Listing only on eBay means you're missing Poshmark's fashion-focused audience. Different platforms have different buyers looking for different things.
The Fix: Cross-list your inventory on at least two platforms. Tools like Vendoo, List Perfectly, and Crosslist make this manageable. More eyes = faster sales.
Mistake #10
Treating This Like a Lottery
Waiting to "find the jackpot"—that one vintage Rolex or rare sneaker—isn't a strategy. Sustainable reselling income comes from consistent, moderate-margin sales, not lottery tickets.
The resellers making real money aren't finding $500 items every week. They're selling twenty $30 items reliably.
The Fix: Focus on repeatable wins: brands you recognize, prices you understand, margins that work. Build a system, not a fantasy.
The Common Thread
Notice what connects most of these mistakes: they're all about avoiding discomfort. It's more fun to source than to list. It's easier to price high than to research. It's simpler to ignore flaws than to photograph them.
The resellers who succeed are the ones who do the uncomfortable work consistently. That's really it. No secret formulas, no hacks—just disciplined execution of basics.
If you're just getting started, don't try to fix all ten at once. Pick the two or three that resonate most and focus there first. Progress beats perfection.