Scoopon currently has Logitech's G27 running as one of its deals, offering the $499 RRP steering wheel and pedal combo for $214.95 delivered. It works out to be 57 per cent off, though in reality it's more of a 15 per cent discount.
Update: Looks like you can get it even cheaper ($195, free shipping) from Logitech Shop. [thanks Nicholas]
http://www.logitechshop.com.au/logitech-g27-racing-wheel-pc-ps3-2.html While the recommended retail price comes in at a few cents under $500, Static Ice shows that stores are selling it for as little as $251 (not including shipping). Still, if you're keen on picking it up, you will be saving yourself around $60 or so (if you factor in $20 for shipping from a regular shop).
The wheel is only compatible with the PC and PS3, so Xbox 360 users are out of luck. At the time of writing, the deal has two days to go, but traditionally these offers end once a certain number of users claim it.