Borderlands 2 £10.18 (~AUD $15) Four Pack £35.65 (~AUD $52) Seasonpass $14.98 USD GamersGate/Steam
Games are listed as steamworks.
Borderlands 2 four pack (PC) £35.65 (works out to about $13aud each according to google's exchange rate).
Also available season pass $14.98usd
Borderlands 2 individual copies £10.18 (about $14.88aud)
Some other Borderlands 2 DLC also discounted (up to 50% off)
http://www.gamersgate.com/borderlands?aff=ggnews (us site)
http://www.gamersgate.co.uk/games?prio=relevance&q=borderlan... (uk site)
The games are listed as 'Steamworks' so I'm assuming after purchase you will get a key to enter into 'activate steam game' and then download the game from steam. (You get the key from 'My Library')
While the game has been out for a while the previous post on it makes it seem like there still is interest out there for the game if you can get 3 others together to purchase it, also seems in the last post people missed out on the season pass which was $1 cheaper than this current price.
Note that there is a US version of the site and a UK version. Main game is cheaper on the UK version and season pass is cheaper on the US version (I am unsure if you can purchase them in the same order but my log-in details do work on both versions of the site).
Also note gamers gate do have a referral system (mine isn't in this post as far as I can tell) so feel free to post your own referrals if you have them. (Seems like you whack a referral string at the end of the item url and link that to people). I'm more just posting this deal because I managed to grab a Bethesda pack from them in their pricing error fiasco and feel guilty of being unlikely to purchase anything else from them.