Online marketplace scams: how to buy and sell safely in 2026

Online marketplaces collectively host hundreds of millions of listings every year. As their popularity grows, so does the frequency of fraud.

According to the FTC's Consumer Sentinel Network, consumers reported losing $16 billion to fraud in 2025—a 25% jump from 2024.¹ Social media platforms, including online marketplaces, accounted for over $2 billion of that figure.² 

Online marketplace scams occur when fake buyers or sellers trick victims into sending money or sharing sensitive personal information. They occur on peer-to-peer marketplace platforms—such as Facebook Marketplace, Craigslist, and OfferUp—and include various types of fraud, from fake payments to counterfeit items.

While scams are widespread across marketplace platforms, they also follow predictable patterns. We’ll cover every major scam type on the most popular online marketplaces, plus practical steps to avoid scams when buying or selling. Learn the patterns, and protect yourself from fraud.

Why marketplace scams surge at certain times

Marketplace scams fluctuate throughout the year. For example, according to the FTC Consumer Sentinel Network, the number of fraud reports originating from social media and websites/apps increased during Q2 and Q3 of 2025.³

The seasonal surge could relate to a growth of online buyers and sellers motivated to declutter during spring cleaning or score bargain deals during back-to-school shopping. More listings create more targets, and more targets create more opportunities for fraud. 

As frauds increase, both first-time and returning users are vulnerable. Buyers and sellers who are unfamiliar with a platform may not be aware of typical scam patterns, while those who irregularly use the platform may not know how patterns have evolved since they last sold an item online.

The most common online marketplace scams in 2026

The sheer volume of online scams can be intimidating, but these scams do show recognizable patterns. Before you list or buy on Facebook Marketplace, Craigslist, or OfferUp, learn the tactics and red flags of the most common secondhand marketplace scams. 

1. Overpayment / fake check scams

How it works:

A scammer poses as a buyer and sends a counterfeit cashier's check or money order for more than your asking price. Then they claim the overpayment was an “accident” and pressure you to quickly ship the item and/or refund the difference. By the time the bank bounces the fraudulent check, you've already wired the "refund" and lost your money and the item you may have shipped.

Applies to: Facebook Marketplace, Craigslist, OfferUp

Red flags:

• The alleged buyer sends “payment” by cashier's check or money order—and significantly above your asking price
• They use urgency to pressure you to quickly repay them or ship the item

2. Venmo, CashApp, and Zelle P2P payment scams

How it works: 

Peer-to-peer (P2P) payment scams occur on payment apps such as Venmo, Zelle, or Cash App. There are two common variations, depending on whether the scammer poses as a buyer or seller.

1. Fake payment screenshot: The “buyer” sends a doctored screenshot that claims they sent payment by Zelle, Venmo, or Cash App. You ship the item, and their payment never actually goes through.
2. Fake shipping insurance request: Before the “seller” ships their non-existent item, they ask you to send a "shipping insurance" or "business account” fee using a payment app. You pay, and they disappear. 

Applies to: Facebook Marketplace, OfferUp

Red flags:

• The alleged buyer insists you pay via P2P payment app instead of the platform’s checkout system
• You receive a payment "confirmation" message that doesn't show up on your app or bank account 
• The alleged seller asks you to send money first before they ship the alleged item
• They use urgency to get you to pay or ship quickly

3. Shipping scams

How it works: 

Like P2P payment scams, the type of shipping scam tactic depends on whether the scammer poses as a buyer or seller. 

1. The “buyer” asks you to ship your listed item. Once you do, their alleged payment never arrives or clears. 
2. In another scam version, the “buyer” claims they can’t pick up the item in person. Instead, they offer to send a courier to pick up your item and pay in cash. They send you a link to pay for the shipping label; the link leads to a fake website that steals your payment details.
3. The “seller” claims they shipped the item after you paid them. You receive an empty box, a counterfeit item, or nothing at all.

Applies to: Facebook Marketplace (especially for shipped orders), Craigslist, OfferUp

Red flags:

• They alleged buyer acts quickly to purchase the item; they often agree to pay your full asking price without negotiation
• The alleged seller provides a tracking number that leads to an unrelated or inactive shipment
• They refuse to meet locally and insist on shipping the item instead
• They are vague about the shipping timeline or carrier

4. Rental and housing scams

How it works: 

A scammer posts one or more rental listings—often copied from a legitimate real estate site—at a below-market price. They pose as a landlord or property manager who is "traveling" or "overseas," and they ask for a deposit for the first month's rent before you view the unit. They disappear once you send payment.

Applies to: Facebook Marketplace, Craigslist

Red flags:

• The listing price is significantly below market rate
• Listing photos appear on multiple sites with different contact info
• The alleged landlord / property manager claims they're out of town and can't show the unit in person
• They request the deposit using wire transfer, gift card, cryptocurrency, or a P2P payment app

5. Car and vehicle scams

How it works: 

A vehicle is listed at a very low price. The seller claims they're traveling, deployed overseas, or experiencing hardship. They pressure you to purchase a VIN report from a third-party site or pay for the car using an "escrow" service they recommend. In both cases, the websites are fake, controlled by the scammer, and used to collect your payment details or sensitive personal information.

Applies to: Facebook Marketplace, Craigslist, OfferUp

Red flags:

• Like rental and housing scams, the listing price is significantly below market value
• The alleged seller uses an elaborate story to explain why they need to sell quickly or can't meet in person
• You don’t recognize the name of the “VIN report” or “escrow” service website they recommend

6. Verification code / phone number scams

How it works: 

Posing as a buyer or seller, the scammer claims they want to verify that you're a real person before moving forward. Google texts you a verification code, and the scammer asks you to read the code over the phone or enter it into a website link.

Once you share the code, the scammer links a Google Voice number to your real phone number. Then they use your number to impersonate you while scamming others. 

Applies to: Facebook Marketplace, Craigslist

Red flags:

• They ask you to "verify" your identity using an SMS code
• They pressure you to confirm the code quickly or move to Telegram or WhatsApp to communicate

7. Counterfeit and empty box scams

How it works: 

You purchase a listed item, typically an iPhone, gaming console, or other high value-electronic device. The “seller” ships the item, but the item shows up damaged, as a counterfeit product, or as a box filled with rocks or paper.

Applies to: Facebook Marketplace, Craigslist, OfferUp (especially for high-value electronics)

Red flags:

• The listing shows photos that lack detail or resemble stock images or images pulled from a retailer's website
• The listing price is significantly below price, with no explanation offered
• The alleged seller won't meet in person or do a live video call to prove the item is powered on and functional
• They try to rush the sale

8. Buyer "dispute" scams

How it works: 

You sell and ship your item to a scammer posing as a buyer. After the sale, the scammer files a dispute with their bank or payment service claiming the item never arrived or was significantly "not as described.” The bank or service issues a full refund to the scammer; they get their money back and keep your item for free.

Applies to: Facebook Marketplace (for shipped orders on Facebook’s checkout system)

Red flags:

• The alleged buyer uses an urgent or eager tone: they don’t ask questions about the item’s condition or history, and/or they don’t negotiate a price
• They insist on a specific payment method, either Facebook Checkout or PayPal Goods & Services

Facebook Marketplace scams

According to FTC data, people reported more money lost to scams originating on Facebook than on any other social media platform in 2025.² As one of the most-used secondhand platforms in the world, Facebook Marketplace is also one of the most targeted by scammers.

Craigslist scams

Craigslist's defining feature—anonymous posting—is also its biggest liability. Unlike other marketplace platforms, Craigslist doesn’t require buyers or sellers to set up profiles, host reviews, or verify their identities. Craigslist’s ease of use also puts you at higher risk for fraud. Learn how to spot, avoid, and recover from Craigslist scams.

OfferUp scams

OfferUp is a mobile-first platform built for fast, local transactions—and that speed is exactly what scammers exploit. Because OfferUp offers relatively strong user protections, scammers take advantage of gaps in the app’s safeguards or pressure you to move quickly off the platform. Look out for scam tactics and red flags unique to OfferUp.

How to protect yourself: Safety rules for buyers and sellers

The most effective way to avoid peer-to-peer marketplace scams is to follow the same rules every time—no exceptions. Below is an overview of key tips to avoid scams when you buy or sell online. 

What to do if you've already been scammed

Acting fast limits the damage and improves your chances at recovery. Here's what to do if you think you’ve been scammed:

1. Block the scammer account and report them to the platform so their account can be removed as soon as possible. (For specific steps on how to block and report a scammer, see our complete guide on what to do after getting scammed on Facebook Marketplace.)
2. Contact your bank or payment app immediately. Some banks can reverse or dispute transfers. While payment apps can’t typically recover your money, they may be able to flag and ban the scammer's account.
3. File a report with the FTC at ReportFraud.ftc.gov. Your report helps the FTC track scam patterns and report to law enforcement agencies.
4. File a complaint with the FBI's Internet Crime Complaint Center at ic3.gov. The IC3  investigates online fraud reports and can pursue criminal cases that involve large financial losses or cross state lines.
5. Place a fraud alert on your credit by contacting one of the three major bureaus: Experian, Equifax, or TransUnion
6. Monitor for identity theft. If the scammer has your sensitive personal information, they may use it to create new identities, take over your financial accounts, or commit tax fraud in your name.

How OmniWatch helps after a marketplace scam

Even after you report a scam, you may be at risk for identity theft or additional fraud attempts. Scammers who collect your personal information during a transaction—your name, phone number, address, payment details, or even Social Security number—may sell or use that data long after the original fraud.

OmniWatch is built to protect you from the possible consequences of data exposure. We offer:

• Up to $50,000 in scam reimbursement coverage—no major competitor currently offers this type of coverage for online marketplace scam losses
• Up to $4 million in identity theft insurance—covers legal fees, lost wages, and recovery costs if your identity is misused
• Dark web monitoring—sends real-time alerts if your personal data surfaces on dark-web forums after a transaction

If you think your information may have been exposed, run a free dark web scan.

Frequently asked questions (FAQs)

This guide is published by OmniWatch. Follow OmniWatch on Facebook for ongoing guidance on identity protection, digital safety, and scam awareness.

1 Federal Trade Commission, New FTC Data Show Big Jump in Reported Losses to Fraud to $12.5 Billion in 2024, March 2025

2 Federal Trade Commission, Reported Losses to Scams on Social Media Eight Times Higher Than in 2020, April 2026

³ Federal Trade Commission, Fraud Facts, FTC Interactive Data Dashboard, April 2026