As far as I know that is against PayPal terms of service.buyer pay paypal fee? it is unusual on the market.
from: https://www.paypal.com/us/webapps/mpp/ua/useragreement-full#accepting-payments
No surcharges
You agree that you will not impose a surcharge or any other fee for accepting PayPal as a payment method. You may charge a handling fee in connection with the sale of goods or services as long as the handling fee does not operate as a surcharge and is not higher than the handling fee you charge for non-PayPal transactions.