I know in terms of cost these don't seem like values but considering what you're actually getting in these I think they are.
Arma X Anniversary Edition - £29.99
(Important note) Buying this through Steam means of course you must play it on the Steam platform meaning you need an internet connection. Buying the boxset off Amazon although a higher cost, does mean you can play without an internet making it more practical for some people
You get every Armed Assault game including the original Operation Flashpoint which is now called Armed Assault Cold War Crisis. The exception being ArmA3 Alpha which is a separate game, Most people will know ArmA for DayZ, but others like myself will know it for the gem of a military simulator it is. The AI is buggy, the story meaningless and the voice acting robotic but in terms of gameplay especially online and thanks to the heavy modding community, special mentions to the Advanced Combat Environment (ACE) Mod, this is a game series everyone should play beyond DayZ.
X - Superbox bundle - £29.99
X (Not to be mistaken by the UFO series), is an open ended space sandbox with a fully functioning economy which the players actions can effect. You can flood the market with low priced goods shattering competition or you could use your ships to launch an embargo against a sector making costs of goods go up. Build up a fleet of warships and head to war with the Kha'ak and Xenon or alternatively declare war on another one of the universes races with the computer AI giving you a good run for your money in a universal war. The opportunities in this game series are unlimited.
The motto of the game games sums it up. Trade, Fight, Build, Think