May I refer you to Jeremy, of Peep Show
"I don't need to pay money to join a gym. The world is my gym. The hills, the trees, the rivers - they are my gym."
That's all you need to know.
I agree with that, but what happens if someone doesn't own a car...
Whenever I can, I arrange with friends to go for a mountain run. It is just not as often as I would like it to be. Mountain is far away- I don't own a car to go alone when I am available.
The public training stadium is also far away. So, I basically train on the asphalt, it is the only thing I can do for the moment. I also do yoga and body pump at home through internet. For now, I am sticking with this no gym solution because there is a strong possibility that I might move from this area.