"clicking them to cost them that fraction of a cent." ahahah, I remember when I tried some paid advertising on facebook for my game, 2 weeks later I visited my mother proudly saying : - 'Me and my friends see a lot of your commercial on FB, we click on it every time to help you !' - 'Please stop doing that !' It costed a lot more than a fraction of a cents by click :p but I putted a low amount and I assume prices are degressives.