Ask HN: What are the options for micro-payments?

Say you expect lots of $1 to $5 transactions. Who offers the best easy-to-integrate service with low enough fees to make it worthwhile?

If I remember correctly Amazon Payments had reduced fees for <$10 transactions. That seems to be gone.

Not sure what PayPal offers but they can be a bit scary due to their history of freezing accounts, etc. High sales velocity could trigger these actions and it would be catastrophic.

I am after a platform with favorable terms for micro-payments and decent rates above that range.