Check out the Humble Bundle -

[Unhinged]

I've not had chance to play Arma yet - but Humble Bundle are currently doing an ARMA bundle - for £15 ish, you can grab yourselves a copy of lots of ARMA, including loads of the add ons (arma 2: British Armed Forces, private military company and Czech Republic).

Here's a link :

https://www.humblebundle.com/arma-bundle

EDIT:  When I said £15... it's actually in $$$... so that turns out to be £12...

[TwoBad]

Hi Unhinged, welcome to dMw and the forum.  If you've bought Arma 3 i hope to see you on our server soon.

Sulky has already posted about the Humble Bundle.  Unfortunately, as Puff says it doesn't include most of the DLC for Arma 3.  I suspect we'll get some deals later this year when they start bringing out the new DLC for this year, including Jets and Tanks.