Not sure if any of you heard of this game ever, but https://cosmoteer.net/
has always been free.
It's a space survival game where you build your own ship on the spot and keep upgrading it as you kill enemies, really addictive. Get some mods for it and suddenly you have a plethora of choices to annihilate your enemies with. Hell, you want to make a flying 51st sign? Go for it, it's possible. Maybe even a flying middle finger. The only thing holding you back is your imagination.