Sorry both wrong. The price is an invitation to treat, recieve an offer for the goods.
Under UK law, the price tag on an item displayed in a shop window (or advertised over public media) is an invitation-to-treat and not an offer of sale (the acceptance of which constitutes a contract).
Once you have agreed a price you have made a contract even if its verbal. Hence ticking the Terms and Conditions box constitutes agreement of a contract between both parties.
So to answer the question even if the seller says it includes other services such as paypal protection its all conditional upon an agreement between both parties. Thus there is no right or wrong on who pays what.