Before you buy anything on Steam, check Green Man Gaming
Green Man Gaming
Use the following code:
GMG30-ALIEN-SDEAL
$35 USD and they give you a steam key. Code above is valid till 25th Jan.
They've also promised that if any publishers approach them and force them to hike up the price for AU/NZ region you can use this code to get an additional 30% discount:
GMGAU-3J9MF-MUINW
^^ Code is valid
for the next 10 years. Support them, they're finally making a stand against AU/NZ price gouging.
Escapist article about this if you want to read more:
http://www.escapistmagazine.com/news...-Price-Gouging