Google had their Stadia Connect today and gave some gameplay previews and more details on Stadia. Stadia will have two tiers:
Stadia Pro: Allows for up to 4K/60 fps HDR with 5.1 surround sound (provided your bandwidth can handle it), as well as select free games and discounts on games to purchase. This tier will cost $9.99 per month. Annual pricing was not announced at this time.
Stadia Base: The free tier that will be available starting in 2020 (once we’re in the post-Founder’s Edition phase of launch) includes up to 1080p/60 fps video and stereo sound and the ability to play games in a Chrome browser or via Pixel 3/3a (with more phones getting access later on).
Along with the tiers, they are accepting preorders today for Stadia Founder’s Edition which includes Chromecast Ultra, a Night Blue Stadia Controller and 3 months of Stadia Pro + 3 month buddy pass.
To preorder: https://store.google.com/product/stadia_founders_edition
