What is online arbitrage? Online arbitrage is buying products from online stores at a low price (a sale, clearance, an open-box listing or a restock) and reselling them on a marketplace such as eBay or Amazon for more. The profit is the difference between what you paid and what you receive after marketplace fees, shipping and any returns. This guide explains how it works, shows the fee math with a worked example, and covers what can go wrong. Fees were checked on November 10, 2026 on eBay's and Amazon's own pages. Fees and rules change, so recheck before you buy inventory.
None of this is a promise of profit. Prices drop after you buy, items come back, and some stock doesn't sell.
How does online arbitrage work?
The loop has four steps:
- Find a price gap. An item is cheaper at one online store than it sells for on a marketplace.
- Check what it actually sells for. Asking prices are hopes. On eBay, look at sold listings for the same exact product; our guide on how to find products that resell shows the method.
- Do the fee math (the section below) before you buy, not after.
- Buy, ship to yourself, list and ship out. The buyer pays you through the marketplace.
Nothing in the loop is secret. What separates a good buy from a bad one is accurate numbers and timing.
Online arbitrage vs retail arbitrage
Retail arbitrage means finding the discounted item in a physical store and reselling it online. Online arbitrage means finding it on a website, so you never leave home, and the item is shipped to you before you ship it on. The resale step is the same.
Our own lowkey flips coverage sits in the same family: staff look at releases outside the big hype categories (video games, collectibles, Hot Wheels, steelbooks) and post what it costs, what it should resell for and what the retailer allows on cancels and returns. Our lowkey flips page describes what a call includes. Arbitrage is the general method; a call is one team's read on one item.
Where does the buying come from?
In general terms, the price gaps people look for come from:
- Retailer sales and clearance. A store marks something down while it's still in demand elsewhere.
- Open-box and returned items. These are cheaper, but condition and what the listing says matter. If the item arrives different from what you expected, you absorb it.
- Restocks. A sold-out product returns to a retailer's site for a short window. Our explainer on how restock monitors work covers why speed matters here.
- Gift-with-purchase and promotions. A free item attached to an order can be worth something on its own; see our LEGO gift-with-purchase and retiring sets example.
Retailers set their own limits, cancellation rules and return windows. Read them before you buy, because they are your way out if the market doesn't move.
Online arbitrage fees: where the money goes
Marketplace fees are the biggest cost people forget. From the official pages we checked on November 10, 2026:
| eBay | Amazon (Individual plan) | Amazon (Professional plan) | |
|---|---|---|---|
| Plan fee | None required | $0.99 per item sold | $39.99 per month |
| Percentage fee | 13.6% of the sale total, up to $7,500 per item, in most categories | 15% in "Everything Else" (minimum $0.30) | Same percentage |
| Per-order fee | $0.30 (order $10 or less) or $0.40 (over $10) | None (the $0.99 item fee applies) | None |
| Trading cards | 13.25% | No card row on the page | No card row on the page |
Sources: eBay's selling fees page and Amazon's seller pricing page, checked November 10, 2026. eBay's page says the total amount of the sale includes the item price, handling charges, shipping collected from the buyer and sales tax. Amazon's page says an item's total price includes its list price and shipping costs. Amazon's rate varies by category (video games are also 15% on the page; consoles are 8%), so check your category. For the formula in detail, see eBay seller fees 2026 and the reseller fees guide.
Worked example: one $50 item
Illustration with made-up inputs. Assumptions:
- You buy the item online for $30, shipping free, tax already included.
- You sell it for $50 and the buyer pays $6 shipping, a $56 total.
- No sales tax is collected on the sale, which keeps the arithmetic simple.
- Your real postage and packing cost is $6.
- Amazon is "Everything Else" at 15%, merchant fulfilled (you ship it yourself).
| eBay | Amazon (Individual) | |
|---|---|---|
| Percentage fee | 13.6% of $56 = $7.62 | 15% of $56 = $8.40 |
| Flat fee | $0.40 | $0.99 |
| Total fees | $8.02 | $9.39 |
| $56 in, minus $30 cost, minus $6 postage, minus fees | $11.98 left | $10.61 left |
On eBay, $11.98 on $30 spent is about 40% before your time, packing materials and any returns. That is the number to judge a buy by, not the $20 gap between $30 and $50.
What if the price drops?
Take the same item selling at $40 instead (a $46 total). On eBay: 13.6% of $46 is $6.26, plus $0.40, so fees are $6.66, and $46 minus $30 minus $6 postage minus $6.66 leaves $3.34. A $10 price drop took roughly $8.64 off what you keep, because the fee shrinks only a little. Thin margins disappear fast, which is why arbitrage sellers check sold listings again right before they buy.
What can go wrong with online arbitrage?
- Price drops. More sellers list the same item, or the retailer restocks, and the resale price falls after you buy.
- Returns. On eBay, if an item doesn't match the listing the buyer can return it and the seller pays return shipping, per eBay's Money Back Guarantee (see our video game guide). Confirm your retailer's return window before you buy, since a return to you may not be possible later.
- Restricted brands and categories. Amazon's seller FAQ says some categories need approval or the Professional plan, and in some cases you need to apply for a product, category or brand. We couldn't confirm which categories are gated for you, so check inside your own Seller Central account, and don't try to list around a restriction. Our Amazon seller guide has the details we could confirm.
- Cancelled or limited orders. Retailers can cancel orders or set per-person limits. Don't spend money you need on a purchase that might not ship.
- Fees you forgot. Shipping supplies, your time, and sales tax all show up later.
- Account flags. Marketplaces enforce their own rules on listings and sellers. Read them before you scale.
Where to sell: eBay or Amazon?
For one-off, used or vintage items, and for trading cards, eBay is built around your own listing and has a published card rate. For new, sealed products that already have a product page, Amazon attaches your offer to a shared page, subject to its approval rules. Many sellers use both. Our eBay vs Amazon comparison has side-by-side fees for $50 and $150 sales, and the eBay pillar guide walks through listing and shipping.
Why speed and information matter
An online price gap often lasts a short time. A product goes on sale, a restock lands, a coupon stacks, and then the listing sells out or the price corrects. A tool that checks a page continuously can alert you faster than you can refresh it, which is the idea behind a restock monitor. Information matters as much: someone has to say what the item sold for, what the retailer allows and when to skip. That is what our staff post in the Discord; what a call looks like is on the lowkey flips page and the resell group page. Most members check out manually from their phone.
How to start with online arbitrage
- Pick one category you understand.
- Find three items and check sold listings for each.
- Run the fee math at a lower resale price than you expect.
- Read the retailer's cancel and return policy.
- Buy one, sell it, and compare the real number with your estimate.
Start small. One item teaches you more about fees and shipping than a spreadsheet.
Sources (checked November 10, 2026)
- eBay: Selling fees
- Amazon: Seller pricing
- Amazon: Seller FAQ (category approval wording, read November 6, 2026)
All worked examples are our own arithmetic on labeled assumptions, not marketplace figures. Results vary by item, shipping cost and tax.
eBay is a trademark of eBay Inc. Amazon is a trademark of Amazon.com, Inc. Friends & Family is an independent reselling community and isn't affiliated with, endorsed by or sponsored by eBay or Amazon. This is educational, not financial or tax advice, and resale prices aren't guaranteed.
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