At most auction houses you would pay 15-20% plus vat as would the buyer, ebay only charges the seller so it does encourage bidding, but don't forget you also have to pay to receive money through paypal.
You could have a stall at an autojumble or use facebook but I don't know anything about that.
Ebay charges about 10 to 15% percent of the total price and that is including postage! Paypal is indeed charging an additional fee and a very unvarouble exchange rate GPB to EURO (this applies to me as I live in the Netherlands). I have tried to sell some parts via ebay and in the end I paid around 23% to Ebay and Paypal. I quickly stopped doing that.
Alernatives are of course the "for sale/wanted" section of this forum and I use Facebook sometimes too.