Mistakes to Avoid When Selling Stuff Online

Key takeaways

Money showing in your account balance does not mean a check has cleared; banks must make funds available quickly, usually within two days, but a fake check can take weeks to detect.
Refusing to return a surplus can feel awkward, but a payment above your asking price followed by a refund request is a scam, not a buyer’s honest mistake.
A payment screenshot on a buyer’s phone proves nothing; confirm every payment inside your own bank or app account.
Do not share verification codes, bank details or your phone number with strangers who want to ‘verify’ you.
If a sale goes wrong, report it to your bank, the selling platform, the FTC and local law enforcement.

Most scam advice is written for buyers, which makes sense because buyers are scammed far more often. But if you list a couch, a phone or a used car for sale, you become a target too. You are holding something valuable, you want the sale to happen, and that eagerness is exactly what a fraudster exploits. The good news is that nearly every seller-side scam runs on the same small set of moves, and once you know them, they are easy to spot.

Why Sellers Are Targets Too

Regulators at the Federal Trade Commission (FTC), the agency that enforces consumer protection law in the United States, warn that fraudsters treat every person as a possible mark and are skilled at unsettling someone just long enough to strike. When you are selling, the pressure runs in a different direction than usual: instead of a stranger pushing you to buy, a stranger is pushing you to ship, refund or hand over details.

A seller scam works because the roles feel reversed. In most fraud, you are asked to pay someone. Here, someone appears to be paying you, which lowers your guard. The scammer’s goal is still the same: to get money or information out of you. The payment that arrives may be fake, inflated, or simply a picture of a payment that never happened. Many of the same warning signs that show up in other schemes, such as urgency and pressure to skip steps, appear here too. Our guide to spotting imposter scams covers those shared patterns in more depth.

Mistake 1: Shipping Before the Payment Actually Clears

The mistake: a buyer pays, you see the money in your account balance, and you ship the item. Days or weeks later, the payment vanishes and the item is gone.

Here is the mechanics. When you deposit a check, federal rules require banks to make the funds available quickly, usually within two days. That availability feels like confirmation, but the FTC is blunt about the difference: a bank calling a check cleared is not confirming the check is genuine. Working out that a check is counterfeit can take the bank weeks. By then, the scammer has the item, and the bank removes the full amount from your account. You may also owe fees for the bounced deposit.

What to do instead:

Never ship or hand over an item until the payment has fully settled, not just appeared in your balance.
For local sales, many sites recommend meeting in person and accepting cash only.
If you accept a check from a stranger, treat it with suspicion. A genuine buyer has no reason to rush you, so give the deposit real time to settle.

Mistake 2: Refunding the Difference on an Overpayment

The mistake: a buyer offers to pay more than your asking price, or sends a check for too much, then asks you to refund the surplus. The FTC calls this a check overpayment scam, and it targets people selling cars and other valuable items through classified ads and online listings.

The script is predictable. The scammer replies to your listing, offers to buy, then invents a reason the payment is larger than agreed, such as an accidental double payment or a fee they claim covers shipping. They ask you to deposit the check and send back the difference. The check is fake, but the deposit shows up in your balance, so you send the refund. When the bank discovers the counterfeit, you owe the full amount, and the scammer has walked away with your money and sometimes your item. BBB data from 2025, cited in one industry analysis, put the median loss in fake check overpayment scams at $1,500.

Red flags the FTC and credit union guidance highlight:

Payment for more than your asking price, for any reason.
Pressure to act now or lose the offer.
A request to refund the difference by wire transfer, prepaid debit card, gift card or cryptocurrency. Once you send money through those channels, it is like handing over cash and it is hard to get back.

What to do instead: turn down any check written for an amount above your asking price, and never send money back to someone who claims they overpaid you. If a buyer genuinely makes an error, tell them to cancel the payment and send the correct amount. If you do accept a check, ask for one issued by a bank in your area, ideally with a branch you can visit in person, so staff can confirm the check is genuine before you deposit it.

Mistake 3: Trusting a Payment Confirmation Screenshot

The mistake: a buyer sends a screenshot showing “Payment Successful” and expects you to ship on that basis alone.

A screenshot is not proof of anything. One analysis of fake payment scams describes the common variations: an edited screenshot where the amount has been changed, an old screenshot from an earlier transaction presented as a new one, a fabricated app interface, and fake text messages or notifications that imitate real payment alerts. These images look convincing because they borrow familiar visual cues, such as checkmarks and success banners, that people see in genuine payments every day.

The core problem is simple. The confirmation lives on the buyer’s device, not in your account. It says nothing about whether money actually reached you.

What to do instead: verify every payment on your own side of the transaction. Open your own banking app or payment account and check the transaction history yourself. If the money is not in your account, the sale has not happened, no matter what the buyer’s screen shows. The FTC adds a related rule: do not accept a mobile payment from someone you do not know at all.

Money tip: Make it a habit to confirm every payment inside your own bank or payment app before you ship. If the money is not visible in your account, it has not been sent.

Mistake 4: Moving Off the Platform to ‘Simplify’ Payment

The mistake: a buyer asks to complete the deal by email, text or an app you have never used, away from the marketplace where you listed the item.

Selling platforms exist between you and the buyer for a reason. The FTC advises sellers who are not selling locally to check what seller protections the site offers, and those protections generally only apply while the transaction stays on the platform. A buyer who steers you off-platform may be trying to escape them.

Once you are off-platform, new angles appear. One version described in industry analysis involves emails that impersonate a genuine payment service, claiming the buyer’s funds are being held back and will only be released once you pay an upfront fee or return an overpayment to convert your account to a “business account.” Sellers who pay out of their own balance later discover that no money ever reached the payment processor.

What to do instead: keep the transaction on the platform, or use a method you have vetted yourself. For big-ticket sales such as cars, the FTC suggests considering an escrow service or an online payment service. An escrow service is a neutral third party that holds the buyer’s money until both sides have done their part, which protects you from a bounced payment. If a buyer proposes a service you know nothing about, investigate it before agreeing: review its website, call its customer support line, and read through its terms of agreement and privacy policy. If you do not feel comfortable with it, do not use it.

The mistake: a buyer who seems cautious asks you to prove you are real, and you hand over a code, a phone number or account details.

The FTC describes one such trick. A supposed buyer claims to worry about fake listings and needs proof that you are a genuine seller. They text a Google Voice verification code to your phone and want you to send the digits back. Share them and the scammer can set up a Google Voice number in your name. That gives them cover for their identity, and anyone who traces their scam calls ends up at your real number.

Other details carry risks too. A verification code is never something you share, because it protects your accounts, not the buyer’s. And if someone who was never part of the sale later offers to recover money you lost, be wary if they ask for your Social Security number or bank account details so they can “deposit a refund” directly. The FTC warns that refund and recovery scammers use excuses such as processing fees or account numbers to get either your money or your information.

What to do instead: a genuine buyer does not need your verification codes, your bank details or your help proving your identity. If a conversation turns toward codes or credentials, end it.

What to Do if a Sale Goes Wrong

If you think you have been targeted or have already lost money, act quickly:

Contact your bank or payment service and report the problem. Ask what options exist for reversing the transaction.
Report it to the selling platform, so the account can be flagged and other sellers protected.
Tell the FTC at ReportFraud.ftc.gov. The FTC uses these reports to build cases against scammers, and other law enforcement agencies can see the reports and use them in their own investigations.
Tell local law enforcement, especially if you lost a significant amount or met the buyer in person.

Talking the situation through can help as well. The FTC suggests sharing the story with a family member, friend or neighbor: saying it out loud can clear your head, and your account might stop someone else from being taken in the same way. Our step-by-step guide explains how to report a scam in the United States.

One last caution applies after the fact. If a stranger contacts you claiming they can recover the money you lost, in exchange for a retainer fee, processing fee or similar upfront payment, that is a recovery scam. Government agencies and law firms do not cold-call victims and demand fees in advance to retrieve money. Scammers also trade lists of people who have been scammed before, expecting them to be good targets for a second attempt.

Common questions

Q: A buyer sent me more money than I asked for. Should I just refund the difference?

A: No. An overpayment with a request to send money back is a well-documented scam. The original payment is usually fake and will be reversed, leaving you out both the item and whatever you refunded.

Q: The money is showing in my bank account. Is the check safe now?

A: Not necessarily. Banks generally have to make deposited funds available within days, but that is availability, not clearance. A counterfeit check can be discovered weeks later, and the bank removes the full amount from your account.

Q: Where should I report an attempted scam when selling online?

A: Start with your bank or payment service and the platform where you listed the item, then report it to the Federal Trade Commission at ReportFraud.ftc.gov. You can also tell your local law enforcement agency.

Q: Someone sent me a verification code and asked me to read it back. What is happening?

A: They are likely trying to set up a Google Voice number in your name, which lets them hide who they are while scamming other people. Do not share the code with anyone.

This article is for general information and education only and isn’t personal financial, tax or legal advice. Rates, fees and rules change, so check current details with the provider or an official source before making decisions.