PlayStation Store offer downloads of Rocket League for PlayStation 4 for $9.99. (Amazon matches this price.) That's $10 off and the best price we could find.

They also offer downloads of Rocket League: Game of the Year Edition for PlayStation 4 for 12.49. (Amazon again matches this price.) That's $13 off and the best price we could find. This version includes additional content and customization, among other things. Both deals ends July 19.