Visit the audio section of your library. Libraries typically feature a collection of records, tapes and compact discs. If the library has a media player, listen to your selection using headphones -- bring your own if you don't want to use headphones that have been worn by countless other heads -- or you can check out your selection to play at home by using your library card. Some libraries, notably those on college campuses, have listening rooms specifically designed to study audio.
Listen to free full-length music at websites such as Duck.FM, Jango or Pandora. Type in the name of your favorite band where instructed (usually on the opening page of the site) and hit "Return" on your keyboard. The website will start playing music by this band or music that is similar to the style of the band. All three of these websites, upon registering, will allow you to customize your own radio station (though you do not have to register to hear the music). Duck.FM will let you download free MP3s once you register. Further, an extensive range of Internet radio stations are available in iTunes, which is a free media player available from Apple. Click on the "Radio" tab in the top left corner of the iTune's interface, which will reveal a list of radio stations. Each of these stations plays free full-length music.
Check out the entertainment section of your local newspaper for free outdoor music listings. Los Angeles, for example, plays host to the Pershing Square Summer Concert Series, which is five weeks of free outdoor music. Harborplace in Baltimore will host the 2011 Lunch Break Concert Series, which will feature ensembles, bands, orchestras and choral groups from schools across the country. New York City in particular offers live music celebrations through the year, mostly in Central Park -- all of which are free.