Party at the park

How do you get a park shelter to use for a small party?

So the state has these parks with old shelters that are run down the benches broken and the ceiling of the shelters full of birds birds nest even bats

Most of these places are abandoned no one uses the city's park shelter it's wood open just has a roof and a few wood benches

So my question is online it says to reserve or rent a shelter it's $200

But its a community park isn't it free?