There are sound effects libraries that cost more than a small car, and they’re probably worth it to certain kinds of users — like movie studios or audio production houses — but not to me. In search of interesting, appropriately licensed sounds for personal amusement, some google searching led me to Freesound.org, which has many thousands of freely usable, user-contributed sound recordings, all Creative Commons licensed. ..

Freesound really is free, too, though donations are accepted; it started as a project of the Music Technology Group of the Universitat Pompeu Fabra. One (very small) catch: you can listen all you want just by visiting the site; downloading the files requires free registration.

Examples, Inspiration, and How-to: from Radio

Third Coast International Audio Festival

Based in Chicago, the Third Coast International Audio Festival (TCIAF) curates sound-rich audio stories from around the world and shares them with as many ears as possible – on the radio, on the Internet, and at public listening events all over the place. Operating year-round, Third Coast offers producers and listeners a multitude of ways to celebrate audio storytelling:

• IT’S AN AUDIO LIBRARY This website is packed with more than one thousand audio stories of all stripes, producer interviews, weekly podcasts, archived conference sessions and the latest Festival happenings.
• IT’S A WEEKLY RADIO SHOW
• IT’S A NATIONAL RADIO SHOW  Best of the Best: The Third Coast Festival Broadcast showcases the winners of the Third Coast / Richard H. Driehaus Foundation Competition and airs on stations across the country each fall.
• IT’S A PODCAST The weekly Third Coast Podcast, hosted by Re:sound producer Katie Mingle, presents Re:sound episodes and special features from our vast audio library.

Transom.org 

iA ublic radio-related site with lots of good info — about both audio content and the technology.  Well worth browsing.  And if you’re serious about audio, it’s a terrific site to follow.