You can watch the 2018 animated version of "The Grinch" streaming on Peacock Premium or Peacock Premium Plus with a subscription. It's also available for rent or purchase on Amazon Video, Apple TV, Fandango At Home, YouTube, and Google Play Movies starting around $3.99. The 2000 live-action version starring Jim Carrey is available to rent or buy on Amazon Prime, Apple TV, YouTube, Vudu, and Google Play Movies. The classic 1966 animated "How the Grinch Stole Christmas!" is streaming on Peacock, Hulu, and Sling TV with premium accounts. These movies also show on TV seasonally on channels like NBC and Freeform. There are no current free streaming options for these movies without a subscription.

In summary:

• "The Grinch" (2018 animation): Peacock subscription or rent/buy on major platforms
• "How the Grinch Stole Christmas" (2000 live-action): Rent/buy on Amazon, Apple TV, etc.
• "How the Grinch Stole Christmas!" (1966 animated special): Peacock, Hulu, Sling TV with subscription

This provides multiple streaming and purchase options depending on your preference.