I am a tightwad. This carries over to travel as well. I can be very flexible and put up with a lot for a cheap place to stay so I can have money for food and activities instead. That's why I find couchsurfing so attractive.
To couchsurf is to stay on someone's couch or in their spare room for free anywhere in the world. That's right. You could go to Shanghai, China or Buenos Aires, Argentina and find someone in the network who has a place you can flop for a couple of nights for free!
It is a two-way street though. The idea is that if you have a couch, bed, or even floor that you can let a traveler use, you should return the favor.
The best way to start is to go to couchsurfing.org and register. You don't have to put someone up right away. You could just offer to meet someone for coffee to help be a guide to your hometown/city. Or you could just be looking for a place to stay on your next trip. But if you start hosting, then it builds up credit/references for you for when you need to go somewhere.
Wait! Is it safe?