https://www.pcgamer.com/rocket-leagues-premium-rocket-pass-cosmetic-reward-system-will-cost-dollar10/

Back in May 2018, Psyonix revealed that Rocket League would be getting a Rocket Pass. Similar to Fortnite's pass, the Rocket Pass is a kind of secondary progression system in which players reach new tiers and unlock progressively rarer cosmetic items, rather than earning them solely from drops and loot boxes, which can't be opened without purchasing keys or buying decryptors during special events. 

The Rocket Pass will be split into free and premium modes, with the latter offering many more cosmetics at each tier. During a meeting at E3 last week, game director Scott Rudi revealed that this premium pass would cost $10.