The Fortnite effect has consumers spending more money than ever on those cards that turn cash into digital currency on PlayStation Network, Xbox Live, and the Epic Games launcher. These game cards have seen increased sales in recent months, but with the launch of the Season Four pass for Epic’s battle royale shooter, game card spending reached an all-time high in April, according to industry sales-tracking firm The NPD Group.

“Year to date, accessories and game card spending has grown 29 percent when compared to a year ago, to $1.2 billion,” NPD analyst Mat Piscatella said. “Game card spending has achieved an all-time high, while accessory spending has reached the highest year to date total since 2011.”

Fortnite: Battle Royale is a free-to-play game, but developer Epic has packed it to the brim with cosmetic items that players can spend money on. The studio also often introduces its season passes, which enable players to unlock new outfits and animated dances for their characters by completing in-game challenges after spending $10. Or you can spend more to unlock the content faster.

But since Fortnite: Battle Royale is an online, digital experience, you either need a debit card or credit card to purchase the in-game currency. Alternatively, you can head to GameStop, Walmart, or the local gas station to pick up a currency card. This means you can just use cash to buy things in an online game.

Countless games use this business model. Fortnite didn’t invent it, but its popularity is driving people into retailers to turn their cash into game cards. And while they’re in the GameStop, consumers are also spending money on accessories like new gamepads and, especially, headsets for game audio and communicating with friends online.

“Sales of headsets grew 89 percent in April 2018 when compared to a year ago,” said Piscatella. “Year to date, headset spending has increased 80 percent. The Xbox One Ear Force Stealth 600 Wireless Headset from Turtle Beach is the best-selling headset for both April 2018 as well as 2018 year to date.”