Someone lend me a car...
But I don't think it should be much of a problem. If they want to play technical/hard ball with you, you can point to the Trade Practices Act and the Fair Trading Act whereby if they misprice something on the shelves, then they have to give you the first for free and the second at the actual price.
I've done it before.
Man, that Batmobile doesn't look too bad at all.