The Heritage Centre is free to enter once you’ve bought a parking ticket and it does well to explain the geological processes that created the cove and its surroundings. If you’ve only come to play on the beach and see Durdle Door(in which case I understand the locals call you a ‘grockle’) it may not entertain but if you like to learn and are planning to spend a full day in the area it is recommended as it will tell you all about the other places to see like the fossil forest and give you a plain English explanation as to how to how these features formed and why they are important.