Reseller Taxes & Bookkeeping: The Complete Guide (Poshmark, Mercari, Depop, StockX, Whatnot)

Reseller taxes come down to one sentence: if you buy things to sell for profit, your net profit is taxable business income plus 15.3% self-employment tax, whether or not any platform sends you a form. Everything else, the 1099-K thresholds, the hobby rules, the garage-sale exception, decides how you report it, not whether you owe it. Here's the complete picture for people selling on Poshmark, Mercari, Depop, StockX, GOAT, Whatnot, Facebook Marketplace and eBay, including the bookkeeping that makes all of it manageable.

The 1099-K: what the thresholds actually are now

The 1099-K is the form payment platforms file with the IRS reporting your gross payment volume. After years of whiplash (the threshold was scheduled to drop to $600, then got delayed, then phased), the 2025 law change restored the federal threshold to $20,000 and 200 transactions. So a casual seller who moved $4,000 of clothes on Poshmark may not get a federal form this year.

Don't relax yet, for three reasons. First, states set their own thresholds, and several are dramatically lower: Virginia, Maryland and Massachusetts report at $600, Illinois at $1,000 and four transactions, New Jersey at $1,000. Sell from one of those states and the form arrives regardless of federal rules. Second, platforms can report below the threshold, and some do. Third, and most important: taxability never depended on the form. Profit from reselling was taxable when the threshold was $20,000, taxable when it was headed to $600, and taxable today. The 1099-K changes what the IRS can see, not what you owe.

One more thing the form does: it reports gross. Fees, refunds, shipping labels, none of it is subtracted. Your bank deposits will always be smaller than the 1099-K, and if your tax return reports revenue that looks like your deposits, the IRS matching computer flags the gap. The mechanics of fixing that are the same across every platform, and we walk through them in our 1099-K reconciliation guide.

Hobby, business, or selling your own stuff? Three different tax treatments

Everything you sell online falls into one of three buckets, and mixing them up is the single most expensive reseller mistake.

Selling personal items at a loss. You paid $900 for a couch, sold it for $250 on Facebook Marketplace. No taxable income, and no deductible loss either (losses on personal-use property don't count). But if that sale flowed through a platform that 1099-Ks you, it still has to be reported and zeroed out correctly on your return, or the gross number reads as unreported income.

Selling personal items at a gain. The vintage guitar you bought for $300 in 2009 and sold for $1,400 is a capital gain of $1,100. Held over a year, it's a long-term gain; collectibles have their own rate rules. Occasional, genuine, and different paperwork than business income.

Reselling for profit. Sourcing at thrift stores, bins, pallets or retail specifically to flip is a business, full stop. Profit goes on Schedule C, picks up self-employment tax, and unlocks the deductions: sourcing costs, mileage to the bins, shipping supplies, platform fees, the works. The IRS hobby rules exist for activities run without a profit motive, and hobby classification is the worst of both worlds: income taxable, expenses not deductible. If you source regularly, track your numbers and try to make money, you're a business, and you want to be, because the deductions are real money.

Most working resellers have all three buckets in one account history: the old golf clubs, the appreciated collectible, and four hundred flips. Books that tag which is which are what let you file each correctly instead of paying business tax on your own garage sale.

Reseller COGS: what did that thrift find actually cost?

Cost of goods sold is where reseller bookkeeping either works or collapses, because your inventory doesn't come with invoices. It comes as a $6.49 price sticker, a $400 bin lot, or a $250 liquidation pallet where a third of the units are junk. Two rules make it work:

Rule one: COGS is recognized when the item sells, not when you buy it. Expense your sourcing runs as they happen and every month's "profit" just reflects how hard you sourced. Heavy sourcing month, terrible margins; no sourcing month, fake-great margins. Lenders see through it, and so will you the first time you try to make a real decision with those numbers. Purchases go to inventory; cost moves to COGS at sale.

Rule two: allocate lots at intake. One receipt covering fifty future listings needs to be split when the items enter inventory, not reconstructed a year later:

• Similar items, by count. A $250 pallet yielding 40 sellable units is $6.25 per unit, with the junk written off immediately.
• Mixed items, by expected resale value. An $85 thrift run producing a $120 jacket and eight $15 shirts shouldn't allocate cost evenly. Weight it by what things will sell for, so the jacket carries more of the $85 than a shirt does.
• Cash buys with no receipt: log them the same day. Date, place, items, amount. A garage-sale purchase log kept contemporaneously holds up; one reconstructed at tax time doesn't.

Do this and every sale shows a real margin, dead inventory shows a real loss, and you learn which sourcing channel actually earns more per hour, bins or racks or pallets. Skip it and your margins are folklore. The account structure that supports it is in our free ecommerce chart of accounts template.

Platform by platform: fees, payouts and gotchas

Every platform nets its fees differently, and books that lump "selling fees" into one line can't tell you which platform pays best for your inventory. The quick tour:

Poshmark taxes and fees. The simplest structure in resale: $2.95 flat on sales under $15, 20% above. Simple doesn't mean cheap; 20% is one of the highest take rates going, offset by Poshmark covering shipping labels through buyer-paid shipping. Poshmark payouts are net, its 1099-K is gross, and the 20% between them is your deduction to capture.

Mercari taxes and fees. Mercari has rewritten its fee model more than once in recent years, dropping seller fees, adding buyer-side fees, then reversing course. That's exactly why itemized fee tracking matters: when a platform changes its take rate mid-year, blended books hide it, and you keep pricing against fees that no longer exist.

Depop taxes and fees. Depop dropped its 10% US selling fee in mid-2024, leaving payment processing around 3.3% plus 45 cents. Sellers who moved inventory toward Depop after that change made a smart margin move; sellers whose books couldn't show per-platform margins never noticed there was a move to make. Depop's 1099-K works like everyone else's: gross, reconciled against your net payouts.

StockX taxes and fees. StockX charges a seller fee that starts around 9% and steps down as your seller level rises, plus 3% payment processing. For sneaker and streetwear flippers, per-item COGS is usually clean (you know what you paid for each pair), but volume sellers hit the same 1099-K gross-versus-net gap, and StockX's level system means your fee rate changes over time, which your books should reflect rather than average away.

GOAT. Commission plus a regional seller fee, netted from payouts. Most StockX sellers cross-list here, which makes per-platform margin tracking the interesting number: same shoe, two fee stacks, one answer about where to sell the next pair.

Whatnot. Live selling: an 8% commission plus payment processing, deducted before payout, on volume that looks like nothing else in resale. A three-hour stream can produce 240 low-dollar sales, giveaways and bundles. Giveaways are marketing expense that looks like missing inventory; bundles need their allocated costs; and per-order bookkeeping would drown you. Summary posting per stream night, with a giveaway log, is the pattern that works.

Facebook Marketplace taxes. The wrinkle here is that many sales happen off-platform in cash, which never generates a 1099-K but is exactly as taxable as everything else. Checkout sales get fees netted and reported; local cash sales rely entirely on your own records. Mixed cash-and-checkout selling is where contemporaneous logging earns its keep, because "the IRS can't see it" and "I don't owe tax on it" are very different sentences.

eBay. The deepest fee stack in resale: final value fees around 13%, per-order fees, store subscriptions, promoted listings, international fees, and shipping labels bought inside the platform, all netted from payouts. eBay's managed payments creates enough bookkeeping problems that we wrote eleven of them up separately, and our eBay bookkeeping service exists because of them.

Inventory when every item is one of one

Retail inventory systems assume SKUs: buy 500, sell them down, reorder. Resale inventory is 900 unique items, each with its own cost, condition and story. What works is item-level tracking with modest ambitions: an ID or listing number, what it cost (allocated per above), when it was sourced, where it's listed, and what it sold for. A spreadsheet does this fine into the thousands of items; inventory apps built for resellers do it with less typing.

Two disciplines keep it honest. Count periodically, even roughly, because death piles (sourced, never listed) and dead stock (listed, never selling) are both your money sitting in totes, and if they were expensed at purchase they've been distorting every month since. And write down aged inventory: the $6.25-per-unit allocation that was honest at intake is fiction two years later when the last fifteen units are unsellable. A quarterly look plus a write-down policy changes sourcing behavior more than any lecture, because the books start showing what that eighteen-month-old tote actually earned: nothing.

Resellers who feed phones and electronics into refurbished marketplaces have a deeper version of this problem, per-grade unit costing, which our Back Market and Reebelo guide covers.

Self-employment tax and quarterly estimates

Reselling profit on Schedule C picks up 15.3% self-employment tax on top of income tax, and nothing is withheld from a Poshmark payout. A reseller netting $40,000 of profit can owe $10,000 to $13,000 combined, due in quarterly estimates in April, June, September and January, not in one April surprise. The safe harbor keeps it simple: pay 100% of last year's total tax through estimates (110% if prior-year income topped $150,000) and you're penalty-proof even in a growth year. Mechanically, moving 25 to 30% of every payout into a separate tax account the day it lands turns quarterly payments from emergencies into transfers. The broader income-tax picture for platform sellers, deductions included, is in our seller taxes guide.

The monthly bookkeeping system that keeps all of this sane

Once the structure exists, maintenance is short. Monthly: post each platform's payout summaries (gross sales, fees by type, refunds, labels), reconcile deposits, log the month's sourcing runs with allocations, record giveaways and write-downs, and glance at per-platform margins against last month. Quarterly: rough inventory count, estimated tax payment, and a check on fee lines for platform changes. January: tie every 1099-K to its platform's gross revenue line, already reconciled, and hand your CPA a file that answers questions instead of raising them.

That's maybe two hours a month of disciplined work, or it's ours to do. What it prevents is the year-end reconstruction: fifty-two weeks of netted payouts across six platforms, a shoebox of thrift receipts, and a 1099-K stack that doesn't match anything, rebuilt under deadline. We do those projects constantly as catch-up work, and every one of them cost more than maintenance would have.

When to hire a reseller bookkeeper

Honest thresholds: under roughly $2,000 a month across platforms, a spreadsheet and discipline genuinely work. Past $5,000 to $10,000 a month, or the moment you're sourcing weekly, running three or more platforms, or staring at a 1099-K that includes personal sales, the math flips: reseller bookkeeping done professionally costs less than the mispriced sourcing, missed deductions and mismatch-notice risk of winging it. And if you've got employees, a warehouse, or serious Whatnot volume, it stopped being optional a while ago.

Our reseller bookkeeping service handles every platform above: payout rebuilds, sourcing-run COGS, per-platform P&L and the January 1099-K tie-out, with published pricing from $149/mo and no annual contract. Want proof before you commit? We'll rebuild your most recent month free, all platforms, and send you a 10-minute video of what we found, missed deductions and mystery fees included. Claim the free teardown here. Our free 27-Point Money Leak Checklist covers the fastest leaks to check yourself in the meantime.