If you go travelling solo or together with 1-2 other persons then consider using
Hospitality Club. It's a great organization where you can sleep for free all over the world.
I have used it a lot on my travels. It cuts away a major expense (hotels) and makes it easy to backpack for several months at the time
I have also had some people come and stay in our home. It has been great, since most of the people in Hospitality Club are very interesting.