Visit the Creative Commons home page, creativecommons.org, to search for folk songs from a wide variety of artists and cultures.
Use the site-specific search engine to find folk songs that are downloadable from sites such as Jamendo. These sites honor Creative Commons licenses and only allow public domain or CC-licensed works.
Click on the song of your choice to play a sample. Folk songs tend to be fairly long, so sampling the music before downloading lets you save time and disk space.
Download the file by clicking the "Save" icon. Save the file downloaded to your music directory or desktop. You can repeat this process as often as you like with no cost.