When you're shopping online, do you know if you're getting a knockoff item or the real thing? The answer could surprise you.

A new report by the Better Business Bureau says 1 in 4 Americans has unknowingly bought at least one counterfeit product.

Some of the knockoff goods are shipped directly from China, while others are shipped to resellers in the U.S.

PODCAST:  Walt talks to the Better Business Bureau's Melissa Companick about counterfeit goods and how to protect yourself for News 12 Talks New Jersey: 

"We're definitely seeing counterfeits coming through the big marketplaces like Amazon, like Walmart.com and like places like Shopify," says Melissa Companick, of the Better Business Bureau.

And counterfeiting is big business. In 2017, authorities seized more than $25 million of knockoff merchandise being smuggled into JFK International Airport.

And while shoppers will still find ads promising deals that are too good to be true, the BBB says counterfeiters have become more sophisticated.

"They're offering the products in prices closer to the actual retail, and it's not an immediate giveaway," Companick says.

So what can you do to protect yourself? Experts say watch out for obvious red flags, like grammatical mistakes. Buy from reputable websites, and don't trust social media posts promising low prices.

If you do get stuck with a knockoff item, report it to the Federal Trade Commission – it may not help you, but it could help the feds catch the people responsible.