Simple really - If you find (either by accident, by searching or by seeing it on the news) an auction on eBay where the item is original (to put it mildly ), put a link to it here.
Dunno whether this would be classed under commercial advertising (as per the rules), but just in case make sure that the bid has closed before posting it. i.e. Just check the closing date and make sure it has passed
I'll start off - I found this while I was having a look at the Mirror's website. It was in today's iBlog.
Jet-Powered Milk Float
I think someone was taking Benny Hill's song "Ernie - The Fastest Milkman in the West" a bit too seriously