With the Square Enix weekend, Boundless has a weekend of free play.
The game is pretty grindy if you want to build large things, but overall, I’m still enjoying it. The organized hunts are pretty fun (and you need to do them to get the ore to make your portals run eventually 
It’s a long term game, really, leveling is slow, very little instant gratification, finding gems later on can be immensely frustrating, but overall it’s still a game where everything is built by players.
The community overall is great, with a number of ‘guilds’ maintaining large portal networks between planets which everyone can use (donations welcome, of course).
Give it a look, since it’s free anyway!
Their Discord: https://discord.gg/JdMzAjt
The Steam Page: https://store.steampowered.com/app/324510/