Money Hacker has a list of twelve ways to travel the world without paying. Some are for free lodging, some for travel expenses, so you may have to combine several tips to truly travel free -and none of these ideas involve joining the military! http://www.moneycompare.com.au/blog/12-ways-to-travel-the-world-for-free.php -via the Presurfer
(image credit: Flickr user sharkbait)
That was over a decade ago,though. I don't know if in the Post-9-11 age anyone still uses couriers like that or not or if maybe even if they do all the extra security makes it so that it has to be more of a permanent job type thing than just a weekend here and there kind of thing or if the security might just in general make it too big a hassle to be worth the while nowdays. But it might still be worth looking into for some folks.
http://www.dailymail.co.uk/news/article-1205794/Rape-horror-tourist-used-couchsurfing-website-aimed-travellers.html
Yes, you can sail the seven seas...
Traveling by cargo is quite cheap and something different too.
Luckily my state as many hidden treasures to discover with excellent water-ways and barrier islands. And for my fellow eastcoasters, the IntraCoastal Waterway kicks serious booty.. and it's FREE!!!