What does free mean?

I don’t have very many, but the ios/droid app marketplace is interesting with all the free apps.  I find myself hesitating to pay money for an app, even though having it would be quite useful and I get that the person who wrote it is trying to make a living.  I’ll drop $2 on a cup of coffee, but resist paying 99 cents for a app I know I’ll use?

The I saw this article about trying to monetize blogging and was taken by this quote:

If you are not paying for it, you’re not the customer; you’re the product being sold.

 Interesting thought now when loading a free app.  Do you wonder who is buying you?