The BBB said thousands of people have fallen victim to misleading advertisements, which may even include fake celebrity endorsements.
According to the study, there have been more than 37,000 complaints to the BBB about free trials.
The average amount lost was $186 per consumer.
The BBB said many of the free trial offers are "subscription traps."
They offer products they say consumers can get for free by paying small shipping fees, but the offers often come with fine print that gives consumers a short period of time to receive, evaluate, and then return the products to avoid being charged.
In some cases, people who signed up were charged more than $100 for products they no longer wanted.
Study authors recommend more criminal prosecution to deter this type of fraud.
The report also said social media sites should do more to crack down on deceptive advertising.