What can you get for free?

Chris Anderson has a great comment on his blog this morning regarding free. He talks about the Oprah touch on Suze Orman's "Women & Money". Oprah announced this last week that people should go check out the free download. Well a lot of people did. Did sales suffer? Nope. In fact Chris was able to graph the sales that came out of it on Amazon and it looks like it is now the #1 seller. As Chris says Oprah + Free = Blockbuster. I would agree. So what can I give away for free?