This seems a little naive to me. Google requires you to be logged into a Google account to access the OS. Given that fact they'll have access to everything the user does. So the opportunities to make a profit are endless to the point of being terrifying. They'll be able to datamine your entire Computing experience and they'll have the computing power to combine that with data from other people. "Hey Ford, want to sell some cars? By looking at people's browsing history and calendar appointments we can tell you the hightest concentration of people who need cars will be in these locations at these times"

In that context fees like the $50 a year for Google Apps seem insignificant