Have you checked to see what they offer for that price?
There are benefits to free dog parks and not for sure. I would pay a bit (say $20 a month) if I had access to a great private park.
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - male GSD - born Jan 26, 2012
Koda & Zazu - 4 year old male cats