If I purchase Apple TV, is it possible to prevent others in the home who have access to the TV from purchasing in app movies, etc. ??

Purchases require your Apple ID and password (or Face ID/​Touch ID from a secondary device) [unless you have turned off that requirement]. If others don’t have the password and can’t authorize the purchase on your account, then purchases would be prevented. Others will be able to watch content that doesn’t require a new purchase, and thus potentially mess up your watch history/​watch progress. Others can add their own account, and use that for purchases.

Buy movies and TV shows from the Apple TV app - Apple Support

Rent movies from the Apple TV app - Apple Support

Subscribe to Apple TV channels in the Apple TV app - Apple Support

Purchase from the Store in the Apple TV app on the Apple TV box.

Purchase from the Store in the Apple TV app on a third party device (Samsung smart TV).

Hello, great question, here's what to do! Also and article to help out!

1.Set Up Restrictions: Go to settings on your Apple TV

2.Select Users and Accounts and choose your account

3.Go to Screen Time and enable it if its not already

4.Go to Screen Time Passcode to set a passcode that you only know

5.From there go to Content & Privacy Restrictions

6.Enable it and then select iTunes and App Store Purchases. You can set options for "in-app purchases" to Don't Allow

By doing this you can ensure some privacy!

Set up parental controls on Apple TV - Apple Support