Third place is a free or relatively cheap place to spend time that is not home or work.

In sociology, the third place refers to the social surroundings that are separate from the two usual social environments of home (“first place”) and the workplace (“second place”). Wikipedia

The term “third place” originates from a 1989 book, The Great Good Place by sociologist Ray Oldenberg. Today.com

In Junited, zakb]writes about how mountain trails are his third places:

On “third places”. Juhis talks about meetups as third places. Might be a stretch, but the mountains are my third place. I read this not long after I was thinking about how when I run the local trails I regularly end up having a good yarn with someone. I feel like its a social outing even though I run solo. A bit like going to the pub without announcing it, knowing you’ll run into someone.

In other garden plots of the world