A Better Business Bureau study released Wednesday found more and more shoppers are being scammed by "fake free trials."

The study found millions are being duped by subscription traps and deceptive advertisements offering "risk-free" trials. Thirty percent of victims encountered the ad on social media, according to the BBB. 

Subscription Traps and Deceptive Free Trials Scam Millions with Misleading Ads and Fake Celebrity Endorsements

"Complaints were really starting to pile up so we wanted to let the public know how much of a problem this industry is," Shannon Nelson with the Northeast Florida BBB said. "More people are spending money [during the holidays], not thinking things through because you're just trying to get your shopping done." 

Nelson said the fraudulent companies rarely disclose their terms and conditions when a shopper is signing up for the trial, especially on social media. 

The study found most victims were asked to pay a low shipping and handling cost for the trial but were charged an average $186 when the item was not returned or automatically after the trial ended. Some shoppers were unaware of the condition. 

"[These companies] are hard to track down, there's no phone number, you don't know who to send it back to or who it came from, so you're in a world of trouble," Nelson said. "Before you make any purchase online, verify who you are dealing with."