Last week I saw 1kg of Silver Bullion from the Perth Mint sell...

Last week I saw 1kg of Silver Bullion from the Perth Mint sell for $666 plus delivery on ebay, at the same time I purchased 1kg directly from the Perth Mint for $548 delivered. I dont understand why there is such a substantial premium on ebay, it must be a case of people not being aware of other ways to purchase silver bullion and not understanding how to value it in AUD.