OK, I just found out. Sorry for the trouble.
Receiving payments that are funded by Paypal balance, instant bank transfer, or eChecks are completely free, even with a personal account.
Receiving payments funded by credit card, debit card or buyer credit costs 4.9%.
Withdrawing money from your paypal account is free.
4.9% is seems a little high, but it's only 1-2% more than what a retail merchant pays.