DETROIT -

If you sign up for a free trial, it may end up costing you.

According to a new survey, consumers collectively paid $14.3 billion in unwanted charges last year.

The survey, featured in USA Today, was commissioned by BillGuard, an online service that tracks and alerts customers to these types of charges, which have been dubbed "gray charges."

The report shows that the cost can reach an average of $215 per person per year. 

Free trials that convert to paid subscriptions make up almost half of all gray charges.

Companies like Amazon and LinkedIn offer free trials of upgrades services for a short period of time and start charging when the period is over. However, consumers have had similar experiences with magazine subscriptions, credit reports that claim to be free, and video and music streaming services.

"Many times its the consumer's behavior that triggers these gray charges," says Ron Shelvin, senior analyst at Aite Group, which conducted the survey.

Consumers are more and more likely to use a debit or credit card as payment and make more online purchase. This makes it easier for merchants to keep billing and contact information on file.

In addition, people often forget that they signed up for something, a mistake that merchants count on. 

However, most consumers aren't disputing the charges.

Of all the gray charges last year, the majority were in the range of $20-50 for the year.

"When you look at the small dollar amount, most people are so busy today that it's a hassle trying to get your money back," says Mary Anne Keegan, chief marketing officer for BillGuard. 

BillGuard is working with the Consumer Financial Protection Bureau to help put a stop to gray charges. They are providing CFPB with data about the prevalence of deceptive marketing as part of CFPB's initiative launched last fall to encourage "consumer-friendly innovation" in the financial services industry.