While Fortnite is free to play, the game has earned billions by selling rewards and seasonal battle passes to players. The battle pass is essentially a checklist of goals that gives players in-game cash and unlockable items.
While the battle pass existed in the first chapter, "Fortnite: Chapter 2" makes it easier to track your progress with on-screen notifications while you play, and the goals seem to be a bit easier to achieve overall.
You can purchase the battle pass for 950 V-bucks, the equivalent of $9.50. If you're dedicated enough, you can earn up to 1,500 V-bucks with the battle pass, which is enough to buy the next seasonal battle pass and a handful of other rewards.