https://www.polygon.com/2017/10/3/16410318/gran-turismo-sport-demo-release-date-ps4

Sony Interactive Entertainment will release a free demo for Gran Turismo Sport next week, giving PlayStation 4 owners a brief taste of Polyphony Digital’s new racing game.

Gran Turismo Sport’s demo will be live for only four days, but progress made in the free trial will carry over to the full game. According to a post on the PlayStation Blog, “your earned in-game credit (up to $1MM) and personalized garage vehicles are transferable to the full game when it launches October 17th.”