I believe you are also safe if the buyer sends payment via Paypal as a personal payment, for which there are no fees within the US and half a percent for international payments.
For shipping, Fedex now quotes prices including customs brokerage fees, which are reasonable and can save buyers surprises on the receiving end. Note, the service includes the brokerage fees, not government duties and taxes which are usually paid after shipping on the receiving end before or at delivery/pickup.
One last thing: I place no faith in the PPal Buyers Protection Plan. I had to initiate two claims, one for an amp that was never shipped (as verified by the seller), and one for an amp that was not functional on delivery, and Paypal was useless in spite of ample documentation. If the seller drains their PP account, PP can't do a thing for you. Fortunately I paid with a credit card.