Do celebrity endorsements make you more likely to buy a product? A lot of companies think so, but some less scrupulous businesses are now faking endorsements – using celebrities’ names and photos without their knowledge.

You may have seen online ads that are written to look like news stories that make claims like, “Joy Behar is leaving ‘The View’ to start a miracle skin care product,” or “Savannah Guthrie is leaving the ‘Today’ show.” Both ads are fake, but they can cost people real money.

The ads take users to professional-looking websites that offer free trials of the product, according to Melissa Companick, with the Better Business Bureau. But beware of the ensuing bill.

"Then you find out when you look at your credit card statement, not only have they charged you this shipping and handling fee, but they have charged you $90, $100, $150 for the product, and you’re also enrolled in an auto delivery program," says Companick.

According to a BBB report, misleading "free trial" offers have cost Americans more than $1 billion over the past 10 years. The ads are often for miracle diet products or creams, and they often use the names or faces of celebrities -- without their permission or knowledge.

What can people do to protect themselves? First, be skeptical of any self-proclaimed miracle product. Contrary to what the ads may say, if a product works that well, it would probably be available in stores.

And if a celebrity's endorsement matters to you, check their social media accounts. Often celebrities are outspoken about fake ads that "borrowed" their names, like Savannah Guthrie has been.