First of all, sorry that this comes a bit too late. I have forgotten to share this piece of info yesterday. Arma 3 is currently on sale on Humble Bundle, and you could get it at extra low cost. Humble Arma 2018 Bundle’s recent promotion was officially confirmed by Arma 3 dev-branch activity SITREP #00218 as well. Coming with the name pay what you want, the bundle seems quite affordable.
If you wish to buy the game for a friend or anyone you could enjoy playing with, not only you could buy the original Arma 3, but also get its DLCs for a fair amount of money.
Namely, if you’re wishing to buy the complete Arma 3 package, including the Arma 3 karts, helicopters, and the Marksmen DLC, alongside with the APEX DLC which is considered to be very useful for getting some of the OP military outfits including the map Tanoa, then you can get the whole package for just $20. This amount is way too low considering the retail Arma 3 price on steam, including the DLCs.
Do not forget that you will get Arma Cold War Assault, Arma Gold Edition, and Arma Tactics, which are also included in the Bundle for the same price of just $20. You can visit the official link by clicking here. There are still five days left before the Bundle is over.