Is that designer dress you bought Prada or nada?

The last thing you want after spending hundreds or even thousands of dollars on a designer wedding gown or any other product is to find out it's a not-so-fabulous fake.

The New Jersey attorney general and division of consumer affairs recently issued a warning about fake designer dresses being hawked online by overseas retailers. The state says that U.S. buyers purchased an estimated 600,000 to 700,000 bogus dresses in 2013. Purchasers complained that the fake-wear didn't match the online photos and descriptions and were made with inferior fabric and workmanship.

Counterfeiting is a big problem domestically and abroad, with many types of designer goods and other products sold online, in walk-in stores, and by street vendors, including jewelry, artwork, computer software, sporting goods, and even electronics. The New Jersey warning about fake dresses came less than a week before state consumer officials and the local police announced charges against the owner and two clerks at a Seaside Heights boardwalk shop, where officials said they had confiscated nearly $11,000 in suspected fake watches and other counterfeit designer merchandise.

Read more about how to identify and protect yourself from counterfeit products and be sure not to get stuck with bogus cash or cashier's checks.

What to do

Whether it's a designer dress or anything else, buy from a company that the manufacturer has authorized to sell the product. If in doubt, check the manufacturer's or designer's website.

Beware if a designer item is being offered at an unusually low price. There's a good chance it's a knockoff.

Don't buy from street vendors, who are often around one day and gone the next.

If you're unfamiliar with a retailer, check it out by using a Web search and the company's name along with such terms as "reviews" and "complaints."' Check for a report on the company at the Better Business Bureau.

Use a credit card for making your purchase. If an item turns out to be a fake and the store won't take the item back, you can seek a chargeback from the card issuer. If you pay with cash, check, or debit card, it can be much more difficult to obtain a refund, or you could be out of luck.

—Anthony Giorgianni