Lately there has been a huge push into the neglect markets of space sims.
With the recent releases of both Space Engineers, and X-Rebirth; along with the titles Star Citizen, and Elite : Dangerous coming down the tube in the not so distant future - To say nothing of Eve Online's recent Rubicon launch. It's safe to say that the space sim genre has fully made it's intentions to come back a strong contender be known.
It's also about time; as we have seen the same ol' high fantasy/Tolkien markets beat to death; and that horse isn't moving much more.
Space Engineers is still in it's Alpha release; but you can pick up the game's early access via steam for a reasonable 15 dollars; this game is going to be price wise the most bang for your buck. It's already shaping up to be a very powerful sand box game.
X-Rebirth is a little more on the pricey side; and had a disastrous launch. Due to what could be conceived as an overly ambitious launch table. The game was clearly launched unfinished. The EgoSoft developers have been hard at work pushing out hotfixs, and weekly updates -- It's not in a playable form; but i would still recommend waiting another month to pick up that title.
Anyways; stick around for indepth reviews on these titles in short order; but first i need more stick time in the stars.