PayPal do not charge to open a PayPal account and to transfer money from your bank account to your PayPal account.
There are following some fees structure in other cases, such as:
* Receiving payment for goods and services.
* Receiving payments from friends and family made using a debit or credit card.
* Receiving a payment from someone in another country.
For complete information, you can see the fees section of PayPal User Agreement.