Selling on eBay, Poshmark, and Mercari: Fees, Sourcing, and 1099-K Rules

You open the closet, see three bins of clothes you haven’t touched in two years, a pair of barely-used headphones, and a stack of kids’ books the kids outgrew. You think, “There’s gotta be a few hundred bucks here.” Then you open eBay, Poshmark, and Mercari side by side and freeze. Reselling on eBay, Poshmark, and Mercari is one of the easiest ways to turn household clutter into real cash, but the platform you choose changes how much actually lands in your account.

I’m gonna be straight with you: the people who make decent money reselling aren’t necessarily the ones with the best stuff. They’re the ones who match the item to the right platform, know the fees cold, and don’t get surprised by a tax form in January. The good news is the math isn’t complicated. The better news is that for 2025 and beyond, the IRS reporting rules just got friendlier for casual sellers, which means fewer paperwork headaches on small side income.

The three platforms, side by side

Each platform has a personality. eBay is the everything-store with the largest audience and the most complex fee structure. Poshmark is fashion-first, social, and bundles shipping into the buyer’s price. Mercari is the simplest of the three and tends to do well on mid-range household items. Knowing the fee math before you list is the difference between profit and busywork.

Here’s the fee breakdown for 2026, item by item:

• eBay: roughly 13.25% final value fee on most categories (payment processing included), plus a $0.30–$0.40 per-order fee. Store subscriptions run $7.95 to $350/month and can lower fees for high-volume sellers.
• Poshmark: a flat $2.95 on sales under $15, then 20% on sales of $15 or more. Shipping is prepaid USPS Priority (up to 5 lbs) and the buyer pays a flat $7.67 shipping rate.
• Mercari: a flat 10% selling fee, no listing fees, payment processing included. Prepaid labels range from $4.99 for under 4 oz to about $15.50 for heavier items.

On a $50 sale, you’d net about $43 on eBay before shipping, exactly $40 on Poshmark with shipping already covered for the buyer, and about $45 on Mercari before shipping. The “winner” depends entirely on what you’re selling and how heavy it is.

Detail that makes all the difference: Poshmark’s 20% looks brutal next to Mercari’s 10%, until you remember Poshmark hands the buyer a prepaid label. If you’re shipping a 3-pound coat from Florida to Oregon, that label would have eaten your Mercari margin anyway. Always model the full cost, not just the headline fee.

What actually sells (and where)

Fashion and apparel make up over 60% of all resale items globally, and the secondhand fashion market is valued at roughly $210–$220 billion, projected to hit $360 billion by 2030. That tells you where the demand sits. But “fashion sells” doesn’t mean every platform sells fashion equally well.

From what I’ve seen working with clients who picked up reselling as a side hustle, the pattern is clear. Branded clothing, handbags, and shoes move fastest on Poshmark because the audience came there specifically for fashion. Electronics, collectibles, trading cards, and anything quirky or niche sell best on eBay because of sheer audience size and the auction format. Mercari shines on general household items under $50: small kitchen gadgets, toys, books, beauty products still in box. If you’re sourcing trading cards or collectibles, eBay auctions or Whatnot will outprice everything else.

I’ve analyzed thousands of bank statements over the years. Clear pattern: the people who turned reselling into reliable supplemental income weren’t sourcing rare items. They were sourcing what they already owned plus thrift store finds in the $3 to $10 range, then matching each piece to the platform where its specific audience lives. A $40 Coach wristlet from a thrift goes to Poshmark. A $25 Instant Pot still in the box goes to Mercari. A vintage video game cartridge goes to eBay auction.

A step-by-step approach to your first $500

Grab a pen, let’s do the math together. The goal isn’t to “start a business,” it’s to clear $500 from stuff you already own and learn the platforms before sourcing anything else. Here’s the order I’d run it:

1. Walk through your house with a laundry basket and pull anything you haven’t used in 12 months that’s still in sellable condition. Aim for 20 to 30 items minimum.
2. Sort the pile into three groups: branded clothing/bags/shoes (Poshmark pile), electronics/collectibles/anything niche (eBay pile), general household items under $50 (Mercari pile).
3. Search each item on its target platform under “sold listings” (eBay) or “sold” filter (Mercari, Poshmark) to find the realistic price. Not the list price. The sold price.
4. Subtract the platform fee and any shipping you’ll cover. If the net is under $10 for a heavy item, donate it instead. Your time is worth more than $3/hour.
5. List 5 items per day for the first week. Photos in natural light, honest descriptions, accurate measurements. The listings that lie about condition get returned, and returns kill margin.

That sequence gets you actual data on which platform moves your inventory fastest, without guessing.

Here’s a tip that’s worth its weight in gold: track every sale in a simple spreadsheet with sale price, fee paid, shipping cost, and net. After 30 days you’ll know your real hourly return. If you’re netting $50 in profit on 6 hours of work, that’s $8.33/hour, and you’ve learned the actual margin before scaling up.

The 1099-K rule for 2025 and beyond

Here’s the part nobody wants to tell you upfront: even casual reselling can trigger an IRS form, and most people don’t know the rules changed. The One Big Beautiful Bill Act, signed into law on July 4, 2025, retroactively restored the Form 1099-K reporting threshold to more than $20,000 in gross payments AND more than 200 transactions. That repealed the planned $600 threshold that had small sellers worried for years.

In plain English: for tax years 2025 and beyond, you’ll only receive a 1099-K from eBay, Poshmark, or Mercari if you cross BOTH thresholds. For most household clutter sellers, that’s a relief. The IRS published updated FAQs on October 23, 2025 (Fact Sheet FS-2025-08) confirming the new threshold and dropping the older guidance. You can read the official update directly on the IRS site.

Now the catch, because there’s always one. Not receiving a 1099-K does NOT mean the income isn’t taxable. The IRS still requires you to report all taxable income from sales, regardless of whether a form is issued. If you bought a thrift jacket for $5 and sold it for $40, the $35 is technically taxable profit. If you sold your own used couch for less than you originally paid, that’s not taxable (personal loss). The form is a reporting trigger, not a tax-creation event. Also, some states maintain their own lower thresholds, so you might still get a 1099-K from a state even if you fall below federal limits. Check your state’s revenue department site before assuming you’re in the clear.

The pitfalls I see new resellers fall into

Pull up your statement and look at where the leaks happen. The most common mistakes I’ve watched eat people’s margins:

Underestimating shipping weight. A 2-pound listing on Mercari that turns out to be 3.5 pounds at the post office eats your profit through label upgrades. Always weigh before listing.

Pricing emotionally instead of by market. “I paid $80 for this” doesn’t matter if it sold for $22 last week on the same platform. Sold comps are the only price data that matter.

Stacking inventory faster than you can ship. Once you have 80 active listings, you’re not a casual seller anymore. You’re running a micro-business with packaging, tracking, and customer messages every day. Many people quit at this stage because the time math stopped working.

Ignoring the cost-of-goods question on sourced items. If you start hitting thrift stores to source inventory, that $4 shirt you flip for $30 isn’t $30 profit. It’s $30 minus fee minus shipping minus the $4 source cost minus gas to the thrift minus your time. Run that math honestly before scaling.

How to apply this today

The real edge in reselling isn’t finding rare items. It’s recognizing that the platform IS the product: the same jacket nets you a different amount on each site, and the seller who lists in the wrong place is paying a hidden tax on every transaction.

Three profiles, three plays:
• Closet declutterer (one-time $300–$800 goal): stick to Mercari for general items and Poshmark for branded clothing. Skip eBay entirely. The 10% flat fee and zero learning curve match the casual goal.
• Side income builder ($200–$500/month target): run all three platforms. List branded fashion on Poshmark, electronics and niche items on eBay, mid-range household on Mercari. Track the spreadsheet weekly.
• Building toward a real business ($1,000+/month): consider an eBay store subscription once you cross 50 monthly sales, learn cost-of-goods accounting, and start tracking miles and supplies for tax deductions.

Back at the bank we called this “fee leakage”: the slow drip of small percentages that nobody notices on a single transaction but adds up brutally over a year. Two complications to expect when you actually start: items will sell slower than you hoped (list 20 to know what moves, not 5), and you’ll occasionally get a buyer asking for a return on a clearly described item. Build a flat 5% return reserve into your mental margin math. The other complication is overweight shipping. Buy a $15 kitchen scale before you list anything heavier than a t-shirt.

This week, walk your house with that laundry basket, pull 25 items, and list 5 on each platform by Sunday. Then check the IRS guidance on the new 1099-K threshold at IRS.gov and bookmark consumer guidance on selling online at Consumer Financial Protection Bureau. If you’re not willing to spend two hours this weekend testing the actual platforms with stuff you’d otherwise donate, what exactly were you hoping the side hustle would do for you?