Tho' it is common for ebay sellers to indicate, in their description, that there is a surcharge for Paypal, everyone should remain aware that is against ebay policy and, if someone snitches you off, ebay *will*, without notice, cancel your auction (happened to me only once). If one continues to violate this policy they will suspend your account.
Although ebay is about as mercenary a company as has ever existed, I believe the primary reason for their surcharge policy is that ebay and Paypal are both in Calif. where it's illegal to pass on credit card fees to the consumer. Remember when you used to buy gas for less if you used cash? No more.
John Dunn in Boise, ID