https://www.gamespot.com/articles/5-free-games-for-amazon-twitch-prime-members-septe/1100-6461493/

Amazon didn't win over any gamers when it killed off its pre-order discount program recently, but that's not the only video game deal the company offers to Prime members. If you subscribe to Amazon Prime, you also get free PC games through Twitch each month. All you have to do is link your Twitch and Amazon accounts, and you can get free games, plus in-game items for titles like Fortnite and Overwatch. And unlike some competing services, the games are yours to keep forever, even if you cancel your Prime subscription.

Twitch has officially announced its Free Games With Prime for September 2018, which are now available. Between now and September 30, Prime members can download five games: The Adventure Pals, Guild of Dungeoneering, Gunpoint, The Original Strife, and Pumped BMX+.