You probably have some left over from a road trip but you can also find them at antique shops, in the attic or leftover at architectural shops. They might not look this nice or colorful but I'm sure you can make do. Maps, architectural drawings and blueprints all make great wall hangings that are cheap, recycled and interesting.
Check with friends who work at an architectural office or just rummage through the backseat of your car. Chances are you'll be able to find a map or blueprint that would look good framed on your wall. And if you need something with more color, there are always pretty maps available for sale like the one pictured above from TheseAreThings.