The name of this site says it all. They offer a variety of sound effects that are bundled into sets, giving you one click access to dozens of effects at once. No credit card information or personal information is required! Just sign up with an email address or Facebook account and you’re ready to download for free.
SFX Source has a huge music and sound effects library, though most of them are only available for purchase. They do, however, have an entire page devoted to free sound effects. They even have a deal that if you link to their site from your website or blog, they’ll send you their entire free sound effect collection in one big .zip file so you don’t have to waste your time downloading each clip individually. Not a bad trade!
Audio Micro is a really easy site to navigate because their free sound effects collection is easily visible from their home page navigation bar. You do have to sign up for an account with the site in order to access the downloads, but once you get past that step you are free to download your heart out!
Though this site is a little busy, it does have a lot of free sound effect downloads available. You can navigate to them right from the home page and search by categories. Be careful to read all of the licensing information, though. Partners in Rhyme owns some of them, but others they cannot verify the origin of the file.