Online marketplace scams: how to stay safe as a buyer or a seller

A real buyer pays. A scammer asks you to do something first.

The answer in 2 lines. Selling: a buyer who sends a check for more than your price and asks you to send back the difference is running a scam. So is a buyer who sends a payment email and asks you to ship before the money is really in your account. Buying: be wary of a very low price on a popular item and of a seller who wants you to pay outside the site's payment system. Either way, keep the deal on the site, meet locally when you can, and never share a verification code.

The 4 habits that block most scams

Keep the deal and the payment on the site. The FTC says not to buy from anyone who wants you to pay outside the marketplace's payment system: you lose the site's protections.
Check your own account, not an email. Open your bank or payment app yourself to see whether the money really arrived. A notification forwarded by the buyer proves nothing.
Never share a verification code sent to your phone, whatever the excuse ("I just want to make sure you're real").
Sell locally when you can: meet the buyer in person and take cash, as the FTC suggests. As a buyer, pay by credit card or through the site's buyer protection.

Stop: danger

Meeting a stranger: meet in a busy public place, in daylight, and bring someone with you. Don't invite a stranger into your home for an expensive item, and don't go alone to theirs.
Threats or a deal that turns violent: leave and call 911.

Scams that target sellers

The trick	How to spot it
Overpayment by check or money order	The "buyer" pays more than your price and asks you to send back the difference. The check is fake. Even if your bank shows the money, it can take weeks to find out, and then the bank takes it back.
Fake payment notification	An email or text that looks like it comes from a payment service says you've been paid, or that the money is "pending" until you pay a fee or upgrade your account. The scammer hopes you ship before you notice nothing arrived.
"I paid you twice"	The buyer says they paid too much by mistake and asks for a refund. No money was ever sent.
The verification code	The buyer asks for a code sent to your phone. Scammers can use it to set up a phone number or account tied to yours.

What not to do

Shipping or handing over an item before the money is really in your account. Check it yourself in your bank or payment app.
Depositing a check for more than your selling price, or sending money back to a buyer for any reason.
Paying a seller with a wire transfer, gift card, reload card or cryptocurrency. The FTC says paying this way is like sending cash: once it's gone, you usually can't get it back.
Sending a deposit to "hold" an item, a car or a rental you haven't seen.

Red flags for buyers

A price far below market on an item many people want (a recent phone, a game console, a car). The FTC warns that an expensive item at a very low price may be fake.
A seller who "is out of town" and can't show you the item.
A request to pay outside the site, by wire, gift card, payment app to a stranger, or cryptocurrency.
Pressure: "other people are interested, pay now."

Use the site's built-in payment system or a credit card. The FTC notes that credit cards come with legal protections if something goes wrong.

If you've been scammed

You paid by card: call your card issuer and dispute the charge. If you typed your card number on a fake page, have the card blocked: see Lost or stolen card: how to block it fast.
You deposited a check or sent money: tell your bank or credit union right away and don't send anything more to the buyer. The CFPB also suggests alerting the marketplace.
Report the account to the marketplace through its official help or report tool, from inside the site or app.
Report to the FTC at ReportFraud.ftc.gov. Click "Report Now" and answer the questions; it takes a few minutes. For an online scam, you can also file with the FBI's Internet Crime Complaint Center (IC3).
Your state attorney general also takes consumer fraud complaints. Rules and procedures vary by state: find your office with the National Association of Attorneys General map.

Keep everything: the listing, the profile, messages, emails, and receipts or proof of payment.

Good to know

A real marketplace or payment service never asks you to pay a fee to receive money from a sale.
If you forward money for a stranger, you may become a "money mule" and get pulled into a fraud investigation (CFPB).
For links and texts that claim to come from a site or delivery company, see How to spot a scam text message.

Dana lists a stroller online for $120. A "buyer" agrees right away, without asking a single question, then mails a check for $900 and asks Dana to send back the extra $780 "for the movers." Dana remembers the overpayment trick, doesn't deposit the check, reports the profile to the site and files a report at ReportFraud.ftc.gov. The stroller sells the next weekend to a neighbor who pays cash.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on November 5, 2026, for the United States. Confidence: high for the scam patterns and the advice, which come from the FTC and the CFPB; medium for state-level procedures, which vary by state. Each marketplace has its own rules and protections: read its official help pages. This guide informs and is not legal advice.