https://www.gamespot.com/articles/free-xbox-one-games-with-gold-of-september-2018-co/1100-6461451/

Somehow it is already nearly September, and that means the next batch of free Games With Gold titles for Xbox One and Xbox 360 will be available very soon. You've got a short while longer to claim the existing games before this new set of freebies arrives on Saturday, September 1.

The Xbox One freebies are Prison Architect (September 1-30) and Livelock (September 16-October 15), which normally sell for $30 and $10 USD respectively. The Xbox 360 free games are Lego Star Wars III: The Clone Wars (September 1-15) and Sega Vintage Collection: Monster World (September 16-30). The Xbox 360 Games With Gold titles play on Xbox One through backwards compatibility, so Xbox One owners are actually getting four freebies.