Shows up as $4.49 AUD on the phone/tablet but $3.99 USD on the browser. You may be able to save a few cents if you buy in USD then get your bank to do the exchange.
Anyway, this is what they have:
X-Men: Days of Future Past
Fear Itself
Civil War
World War Hulk
Infinity Gauntlet (best deal out of the bunch considering the story and page count)
Spider-Man: Big Time
Wolverine and the X-Men vol 1 (good stuff but only 4 issues/105 pages)
New Avengers: Breakout
Sale ends Jan 5 in the US so I'm guessing roughly Jan 6 for us.
I'm sure mainly only those into comics will buy it, but for anyway else blindly buying one of these collections be careful as for example the 'civil war' and 'world war hulk' do have story beginnings/middles/endings in other comics not in the collections.
You will get the main story and its a great deal, but these Marvel events do branch out to other comics.