DayZ mod question

yes you need both games to play. you can use the free version of arma 2 on steam and then buy the arma 2 OP

You definitely need Operation Arrowhead.

Good luck! It's an amazing experience :)

have a read of this its a guide

http://i.imgur.com/ZWSZd.jpg

You should be able to using the Six Launcher at least!

You do need both (although I've heard some people say you can use Arma 2 free, since OA is standalone), but you can have that on Steam and have the base game on GMG. That's the way I have it, and it works fine.

You operation arrowhead at least and the free version of steam however yo uwil need to apply lots of patches.
Combined Operations its expensive but doesnt take too long to patch

can you expect a price drop soon?

I'll wait for the summer sale, hoping Arma franchise will be daily deal. Then, probably, enormous amount of money gonna get spended)