$35 per year to join my state's Trail Association. After that it's just gas money to get to the hikes, and I get to go to state and regional parks for free, during trail association hikes and events. Also I get free access to most of the amusement lovations in my state, through work. I haven't been able to attend a lot of hikes because of scheduling conflicts, so I also purchased an annual pass to regional parks and will go walking on my own time.
Surfing the Internet, reading blogs, audiobooks on YouTube, which I listen to while working; it really makes the day go by faster. I absolutely love and adore my part-time job (like I would volunteer for free as a docent), so not only is it cheap, but it earns me money. Hanging out with family (for some reason, friends always do things that cost money... but I guess it helps when your family is frugal also). I also spent a lot of time with my pets (they are frugal too).
Come to think of it, I really don't spend that much on regular entertainment. Not necessarily because of money either, I just don't ever seem to enjoy the things many of my peers do, like frequenting restaurants, and doing laser tag, playing pool, comedy clubs, bars. I like trying new restaurants, but I don't need to go back until I've tried everything on the menu for the second time. I'm also not big on mega concerts and rare times I go to concerts, I prefer small intimate settings.