FTL: Faster Than Light [$9.99 (HD)] is currently on sale for $6.99 until July. This coincides with the Steam Summer Sale, where the game is available for $6.99 there as well, so you likely just have until July 1st to get this roguelike-inspired spaceship simulator for cheaper. This is the game's first sale, with the cheapest the Steam version's ever gotten being $2.49 once during a flash sale, last summer, so while the game might get cheaper at some point, now's as good a time as any to jump in.
Here's the trailer if you need a refresher:
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