I normally pirate my games to see if they work with my setup. If they do, there's a chance I'll buy them. But having it just work with Steam is much more likely I just pay a few bucks for a game, rather than look for it on a private tracker.
If it doesn't work, just legitimately get 100% of your money back.
There are different ways to get into trackers, if you want to embark on the journey. You can get an invite directly, you can buy one (against TOS, if they find out they ban you & the inviter usually), there are sometimes free registration periods, and they sometimes do cross-promotion, like if you're a member at X for a time, then you can register to Y.
For games, maybe a lesser PITA is to look for repackers. But of course, as these are on the open internet, there are clones too.