There are 7.8 billion people in the world. If you can get 1% of them to pay you a penny once a year, you're making $780k/year. You can make $100k/year by getting $0.10/year from one person in every 7800. If you can get people to pay you $0.01/week, you can make $100k/year from less than 200,000 people.
But not if your $0.01 transaction has a $0.30 minimum transaction fee.