If you missed out on that brief period of time that Arkham Knight was available on PC, you might want to check out G2A.com. They're still selling it, and the current price is only $16.
You know they're going to fix the PC version eventually. So if you refuse to play the broken (but but still totally playable) version of the game, you can still buy it now, while it's cheap. Because once the PC port IS fixed, you better believe they'll be selling it for $60.