My family recently visited Martha's Vineyard for a week renting a house in Edgartown. As an added benefit this house came with a "Beach Key". A Beach Key is basically a key that gives you access to a private association beach. Its actually a non-buildable, deeded piece of real estate that sells for $225-$350k.
You might wonder why anyone would want to pay that much for essentially access to a beach but it is a very nice amenity.
First I must say that everything on the island is so cryptic. The directions to this special beach are some like ...
Secret Locked gate
Path to the ocean
Path through the dunes
Ahhhh, private beach