Some volunteer programs don't cost a thing for you to get involved in efforts of making the world a better place. You can choose to volunteer for three months, one year, two years or more. And . . . whilst you're at it, you can earn volunteer allowances to spend as you travel through the country you're sent to. What do you think? Would this be a cool way to save money on travel if you have the time in your hands?
I think that if I find a cause that interests me, where I think that I can make a difference, I would certainly join. As you say, not only I would travel "for free" and see the world, as I would also be able to help other people and gain a great life experience... Well done to all volunteers using their time to help others.
If you don't have any strong ties, like a girlfriend or a family that needs you, volunteering to travel for free sounds like a great idea! You get some money for moving to the new location and thus traveling becomes cheaper. There's still work involved, so it's not really just traveling, but you do get access to certain areas and people that you wouldn't have know by traveling as a tourist. I think this way of traveling is more suited for students or people that chose this as a life style since by the time you're 30 or so you can afford to travel as a tourist.
The great sound of the volunteer travel and I think if you are single then you move on because you have not family and I appreciate that type of ideas in free time..