https://www.pcgamer.com/steam-games-sales-stats-biggest-discounts/
If they're not on sale now, they will be soon.
Sort of. It's still at its core a game about exploring the universe(s) alone, so you can't unfortunately just decide to inhabit the same freighter as your friend and adventure with them that way, but it has some multiplayer elements you can participate in if you choose to do so. You can visit each others' freighters and bases, gift the other person stuff and so on, and you can participate in multiplayer Nexus missions (from the Anomaly). There's also pvp as a default option and hence unfortunately a few griefers, but mostly the community is pretty nice. These days they also sometimes run expeditions where everyone does a bunch of tasks starting from the same planet and on largely the same mission route and on those days, the universe feels anything but lonely. People also build bases to simplify expedition tasks and provide handy supplies for other players - and the odd person builds bases to lure you into going there and then have you toasted in a volcano before you've figured out why it's suddenly so darn hot, so, you know, caveat emptor :-).