A pretty good deal at $99.75 at Officeworks with their PBG.
Hasn't dipped below $105 at Amazon this year.
It's a pretty powerful USB WiFi Adapter (alleged speeds up to 1300Mbps), I have a gigabit connection which gives speeds around 800Mbps to the router and I'm getting around 600Mbps at my PC using this adapter wirelessly.
The adapter comes with a pretty neat desktop stand if you don't want the adapter sticking out of your PC wherever you plug it in.
If you can't make it to Officeworks or Umart C&C, it's $107.50 here - only 3 in stock though