Think Android isn’t creating a serious amount of cash for Google? Think again. According to Piper Jaffray analyst Gene Munster, the search giant’s free mobile operating system could generate as much as $1.3 billion in revenue for Google in 2012. With an estimated 133 million users, that’s an annual ARPU (average revenue per user) of roughly $9.85. Translation: every Android handset sold nets Google roughly $10 per year in ad revenues alone. Those are pretty impressive numbers. With over 300,000 new activations each time the calendar turns, Google continues to add nearly $3 million in mobile, ad-driven revenue to its bottom line… daily. If you’re going to give something away for free, that’s how to do it.