@vincent @jack - They sort of do! I think with a normal Prime subscription you can share it with (at least) one family member, and they get their own Prime subscription, at not extra cost. That's the situatin with my wife and I. I have the Prime subscription, but she gets all the benefits on her (separate) Amazon account.
@vincent @jack - Here's the basic info: https://www.amazon.com/gp/help/customer/display.html?ie=UTF8&nodeId=200444180 If you sign in and go to "Your Account," then click on "Prime," Then "See All Your Prim Benefits," Then down at the bottom under "Other Benefits" is a link for "Share Your Prime Benefits" which shoudl take to to where you can add another adult to share your Prime Membership. They also have a "household" thing now which might do the same thing, but that's not how we set it up years ago, and I don't know what, if anythign is different about doing the sharing through a "household."
@jack no need; each person can have their own account, with Prime benefits shared. No need to worry about the other person seeing notifications. For me, I’m the Prime holder, and share it with my wife and mother-in-law. The only downside is our Apple TV needs to connect to my account to watch Prime Channels, and my wife needs to ask me to change the channel lineup.
@vincent one of my ex colleagues did the same. i still have a UK account from when I lived there and can access prime video as well as occasionally getting okay delivery rates but no free delivery. I wondered if prime delivery would extend this far. still, I may investigate (although I try and fail to avoid amazon).