Well depending on where you live, where they live, how big or how heavy the item is and the freight service the $20 postage may be correct. Not likely though.
I sell alot of things on ebay and always charge an extra couple of $ for handling fees (as always stated in my ad's). This goes towards packaging materials, cost of the ad, my time and petrol to get to the post office and back etc. Nine times out of ten i still end up out of pocket though.
As others have said there is a trend on ebay atm, offer a buy it now price of $0.99 and charge $100's for shipping! This REALLY annoys me and does nothing but waste everyones time.
Excessive postage and handling policy -
http://pages.ebay.com.au/help/policies/ ... pping.html