Re free SFX, the best thing to do is an internet search (Google/Bling/etc) with the keywords being the type of FX you are looking for and the words free sound effect. But be cautious because you may get results that are conditional. For example, Pond5 does have a few free SFX but most are for a royalty fee. BBC Sound Effects has a huge library but are royalty payable for commercial use (but not for personal, educational or research use) - http://bbcsfx.acropolis.org.uk/
Music is another matter and usually subject to royalties.
EDIT: Here's a possible free music website which I'd forgotten about (never used it though):