Thanks Anthony, so if I bid $500 on a domain that figure won't show - it will just add $1 to the current highest bid until someone bids higher than my proxy (or if there proxy is higher)?
If you add $500 and there is no other bid it will show as $10, This also makes you eligible for the first bidder discount of $10. So if the auction ended at this point you pay $11 for the auction and then you get a $11 discount for being the first bidder and you pay the registration fee of $49.95 (quoted here including GST).
If another party bids $300 then you are still winning and will be paying $291 ($301-$10 first bidders discount) plus GST, plus the registration fee.
If another party offers $800, then you are no longer the winner but are the underbidder at $500 and they will be paying $501 plus GST plus registration.