Just to put my 2 cents in here:
See this article regarding the topic of whether to pass on paypal fees to your client.
http://justcreative.com/2008/11/13/d...s-paypal-fees/
It is actually against the Paypal terms of service to charge someone a fee to pay you with paypal.
On another note, it is against the Visa and Mastercard terms of service to charge a fee to pay by debit/credit or to say something like "Credit Cards, $10 minimum." Stores do it all the time, but it IS against their merchant agreement for the same reason.
Just something to be careful of.