Are you looking at USD or AUD...there's a difference! If that's not the case then usually it's a pricing error, glitch in their system.
You can get good deals when you look - I recently saw advertised someone who was selling a PM nugget 1 oz gold coin at the price of "2% lower than Perth Mint spot price". I didn't really believe this so asked for photo's etc and got real photo's of what looked liked the geniune article. Guess he needs the fiat. I didn't have fiat to snap up this bargain so it might still be available.