https://www.polygon.com/2018/6/20/17483294/rocket-league-rocket-pass-launch-date-price-explainer

Rocket League’s makers have shared more information about the upcoming “Rocket Pass,” announced back in May, which seems to follow the season pass model of Fortnite and PlayerUnknown’s Battlegrounds.

First, the pass will be available on all platforms, and every item players receive from it will be tradable. The cost to unlock the premium tier of a Rocket Pass will be the in-game equivalent of $9.99, same cost as Fortnite’s “Battle Pass,” which is also a time-limited progression system.