Comment by ayende

The main barrier you will have to deal with is that for most payment providers, the cost is 3%-5% + 0.3 $ - 0.99$ or something similar.

For micro payments, that means that most of your income is eaten by the fees.

Paypal offers micropay option, with a 5 cents plus 5% cost, meaning you'll pay just 10% in fees.

This is part of the reason micropayments are problematic