This would be a violation of PayPal's User Agreement - see below:
[co]
  • 4.5 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.
  • [/co]


    Reference: https://www.paypal.com/webapps/mpp/ua/useragreement-full?country.x=US&locale.x=en_US#4