I bought oodles o' music from here...
http://www.sound-ideas.com/
Haven't bought anything in a few years... but he had it all, for sure.
Some of the prices reflect the sources... but there was a lot of very good budget fare as well, though.
Also, right at about the time that "Flash" was becoming popular, he was bundling cheap CDs for the amateur webdesigners... with loops, tunes and soundFX for web-based multimedia, that sounded good in video, too.
If you are looking for more along the lines of "free"....
http://www.flashkit.com/
Adittionally, you can go to any larger record shop and buy soundFX CDs. They are most normally seen at Halloween time (spooky sounds), but the big stores carry a selection of "everyday" sound FX volumes. Be sure to read the cd-case for permissions, before buying. There was one cd company that would sell the CDs, but not "allow" you to use it for anything, aside from the cd-player. :shock: