Image by donandcarol via FlickrNot a joke, not a scam. A friend at work told me about this program where they give you a brand new car to drive for 2 years--all you have to pay for is gas--they cover insurance and there's no property tax because you don't own it. The car has an ad on it, but who cares? It's free! And you get to choose what kind of car you want and which of their advertisements you want on it. Not a bad deal.
The other option is to let them place an ad (completely removable, no damage) on your own car, and they'll actually pay you. I'm moving fairly soon, but I'm seriously considering taking advantage of this offer after that. I'll keep you guys updated. Apparently you can make around $700/mo, depending on what size ad you choose.
There are a few companies out there--I'm not going to plug any of them, but a Google search should get you what you want to know.
Have you done this or known someone who has? Leave a comment and let us know what you think about it! I'm dying to try it.