You can do pretty well with next to nothing. I spent three months hitchhiking and couchsurfing my way through the US and Canada, covering roughly 20,000 miles and staying with dozens of hosts. I started with $700 in my account, and still had a few hundred left by the end of the trip. Had I wanted to be more frugal, and not get 'local food' when someone suggested something especially good, I probably could have gotten by with less.

So it's true that you need something....but you can do it with little enough that $25 can be a significant part of your budget.

You can. On expense of other people good will. And give them something in exchange. Good company, manual labor, songs, whatever. Of course we need to agree on definition of "travel" first ;)