One way to obtain free guitar sheet music is to go to the local library and make copies of guitar tabs from the available music books. If you have access to a computer, there are websites that have free guitar music available to download and print. Freemake.com has a comprehensive list of websites for downloading free guitar sheet music. The most relevant websites are GuitarTab.com and UltimateGuitar.com. These sites allow you to search public guitar tabs and download to print.
Google images is another free source of guitar sheet music. Once you find the sheet music that you'd like to keep, simply download in PDF or GIF format or copy and paste into Word and print it out.
Websites such as 8Note or MusesShare have archives of free and available sheet music for guitar. Free guitar tabs are generally easier to find than free sheet music because guitar sheet music is subject to copyright. Guitar tabs can be found on most general free guitar tab websites like UltimateGuitar because they are submitted by users.
Alternative options to guitar sheet music include free apps and videos. iTunes has an app that provides fingerings to guitar music and can be downloaded on the itunes website. YouTube channels often provide links to sheet music in their detail pages or will show free tabs in their video.