Free stuff is always good!

1)Sample magic released a demo pack of loops and samples for all the products they released. You can use this free loops:

http://www.samplemagic.com/downloads.html

quick and easy download!

2)http://www.freesound.org/browse/
Awesome for sound effects!

3)http://soundcloud.com/groups/search?q%5Bfulltext%5D=samples+
Use soundcloud to find and download loops for your music library!

4)http://www.musicradar.com/news/tech/sampleradar-13154-free-sample-downloads-217833/79
342 free dubstep samples from musicradar!

and + 10.000 more samples from musicradar: http://www.musicradar.com/news/tech/10000-free-sample-downloads-235814

Cheers!