The base is just because it's the actual game - you can't really run an expansion without the game it is expanding And no - go get your own 4.30!
Yeah you can, hence the term "stand alone" expansion. The mod uses assets from both games though, hence you need Combined Operations to run it. Also the map used is from Arma 2, not the expansion. So yeah, Arma 2 is a necessity.
If steam sales don't happen tomorrow, people are expecting it not to be for at least another week. On the bright side Amazon should have a 25% off tomorrow on the combined package. http://www.neogaf.com/forum/showpost.php?p=39352910&postcount=112
<iframe width="640" height="360" src="http://www.youtube.com/embed/MWf8aZSzQlQ" frameborder="0" allowfullscreen></iframe> Oh fuck me!
It's 25% off here (https://store.bistudio.com/arma2-combined-operations) for 25 bucks. The lowest it will probably go is 22 bucks on steam/amazon because that site is linked to the devs I believe, if they're only doing 25% I doubt steam will go lower.
Got fucking sick of waiting - just bought it from the developer's site for 25 bucks. Waiting a few more days would have save me like 2-3bucks; not worth it. It's the steam version too so all good.