Every month Humble Bundle offer a bunch of games for $12 USD (or less if you subscribe for long periods) and this months main game is Stellaris.
"Stellaris is a 4X grand strategy video game developed and published by Paradox Interactive. Stellaris's gameplay revolves around space exploration, managing an empire, and diplomacy and warfare with other spacefaring civilizations."
If you buy this you are subscribed, if you only want this bundle, cancel the bundle immediately after purchasing and you get Stellaris immediately and the other games at the end of this month. The other games that come with are apparently awesome sometimes too.
**-Edit- I doubt any will read this, but there are also mods for this game including Star Trek and Star Wars that make the base game completely different and awesome.
The DLC is on sale at Humble Bundle store**