The Black Eyed Peas drew a mixed reaction from Twitter users in their halftime Super Bowl performance, but -- love it or hate it -- it might surprise you to discover that the group wasn't paid for its efforts.

In fact, most acts that perform at the Super Bowl aren't paid to do so, according to Forbes.

The reason? These groups stand to gain a lot more from the exposure alone. Last year, a record 106.5 million viewers tuned in to the Super Bowl, and this year's game is expected to exceed that.

"The platform that these artists are given can't be replicated," said Paul Swangard, managing director of the University of Oregon's Warsaw Sports Marketing Center, one of multiple experts who confirmed to Forbes that halftime performances are unpaid. "It's a basic financial equation. What would you have to do as a band to have a conversation with a third of the country? I think the arrangement makes a lot of sense."

Swangard points out that Tom Petty saw a boost in record sales following his 2008 performance and predicts that the Black Eyed Peas will likely see a similar boost.

And there are still perks to be enjoyed. The Peas received funding for the show's production as well as free travel for themselves and their staff.

A rep from the Universal Music Group -- parent company of the Peas' label, Interscope -- did not respond to Forbes' request for comment.