In case you're trying to find details on PayPal's micropayments option of 5% + $0.05 per transaction, it is hidden on their website:
https://developer.paypal.com/
...which briefly describes the alternate pricing scheme for selling low-priced items. You must sign up via this page:
https://www.paypal.com/signup/account
Why is it hidden? I guess they figure everyone else will pay the higher rate, rather than take their business elsewhere...