Now this is a real easy peasy thing to do. Just take any paper that's thick enough to hold as a garland (like ordinary printing paper) and cut out strips of it, glue each piece together to make the garland.
This DIY garland was made by old song book pages, and it's really really pretty!
This one is again something I will be doing. I have so many song books (used to play the piano) that I can easily discard one for this. But maybe a book you don't really like could go as well? Or maybe some nice wrapping paper?