Free Lunch???

One thing puzzles me about blogging. I am a technophobe; yet even I was able to get my own blog up/running in less than five minutes. The "mechanics" are simple and efficient, and so far I have been completely satisfied (blown away) with the result. OK, here's the part I don't understand: This entire process has been FREE--hasn't cost me a nickel! There must be costs associated with operating and maintaining blogger.com and my individual blog site. Who pays? Why?