The Ghosts 'n Goblins DLC is also free for PlayStation Plus members.
Capcom Arcade Stadium is also available for free on these other platforms:
Amazon has The Black Death: A History From Beginning to End (Pandemic History Book 1) by Hourly History (Kindle Edition eBook) for $0 downloaded.
App Store has Marbloid (iOS 10.0+) on sale for $0 downloaded. This 3D marble runner has gotten good reviews and received honorable mention at the 2019 Indie Games Festival.