Robbie,
Before you go to the trouble of listing something on eBay, first do a search of your particular item to see if it is selling. Once it comes up on a list, select the option of showing only completed auctions, because then you can see if it has sold, and for how much. If it doesn't seem to be moving, you would want to reconsider listing it. eBay charges for the listing, and a Final Value Fee if and when you sell an item, a percentage of the total (not including shipping). As smokey suggested, you should be able to find out from a local shipper what it will cost to ship. In any case, the buyer pays shipping costs. Another thing that seems to help make a successful auction is to have a picture or two, and it is worth the extra $.25 (don't know what the UK equivalent is, but it isn't much) to have a gallery picture.
From personal experience, if a printer is more than three or four years old, you're not going to get much money for it. At our local dump here, there is a rather large mound (10 feet by 30 feet by 5 feet high) of "obsolete" computers, monitors, and printers.
Let's face it - most computers are obsolete as soon as you carry them out of the store 
.
Hope this helps a little 
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Mrs. C 
