First-time buyer needing help about buying the game

Hi everyone! I've been lurking here for a little while when I found out the game from my childhood had a subreddit.

My exams are over and am hoping to buy the game. I know that there was a sale on Steam the last time, where it was sold more cheaply, but the current bundle on Steam is a bit pricey at roughly 50 dollars after conversion. Would there be any sales in the future? Also I aim to get into the multiplayer community to play (and get my ass kicked many times over online) with others for the first time, I heard that people play on something called Voobly and some on Steam. If I do get the game, how do I play with others?

Sorry for so many questions... :/