For years, companies hunting for new customers have sent out coupon mass mailings offering free stuff, most of it ending up in the trash. Now, thanks to Facebook, they can zero in on the folks who are genuinely interested.

Amy Guth, the social media editor of the Chicago Tribune, says that with more than 500 million people logged on to Facebook, companies are using the social networking site to get their products in your hands.

Getting a free sample on Facebook can be as simple as liking a company's page. The hardest part can be keeping track of them all. Then there's that must-ask question that comes up when you find anything for free: What's the catch?

"The catch of the Facebook freebie is that once you like the page in order to get the freebie, they have all of your information, and they can use that for their marketing purposes," says Guth. Guth's suggestion is to set up a separate email account dedicated to freebie tracking. That way, any unwanted solicitation will go there and not to your personal account.

There's another catch: The wait. It may sometimes take months, but companies are giving away thousands of dollars in free products all in hopes you'll give them another look when you decide to buy something.