Which music and other elements can i use?

MUSIC

It is always ok to use music you have composed yourself. If you record and use music that is inspired by existing work you have to make sure that you change the original song and lyrics in such a way that it ‘materially changes the original meaning, context or intended communication’. So if you play U2s Sunday bloody Sunday on the piano and sing the original lyrics then it would NOT be copyright free.

You can of course also try to get formal approval by the original artist to use their work. This is not a pipe dream because the artist will get free publicity in return as long as you use his/her name in the credits. If you want to try this route you would need an e-mail from the original artist saying:

I, [artist], give you permission to use my [music] royalty-free for commercial purposes (advertising).

Having said all that, it is by far the easiest way to just use music from a reliable source of
Royalty-free Music for Commercial Purposes:

http://www.royaltyfreemusic.com
http://www.music4yourvids.co.uk/pages/indexpag.html
http://www.freetech4teachers.com/2012/06/5-sources-of-free-sound-effects-and.html
http://www.entropymusic.com
http://www.stockmusic.net
http://www.musicbakery.com
http://danosongs.com
http://creativecommons.org/legalmusicforvideos
http://freemusicarchive.org
http://podsafeaudio.com
http://incompetech.com/m/c/royalty-free
http://soundbible.com
http://www.jamendo.com
http://www.neosounds.com

3D MODELS

http://archive3d.net/
http://archibase.net/
http://archibaseplanet.com/

IMAGES

http://en.wikipedia.org/wiki/Wikipedia:Public_domain_image_resources
http://www.flickr.com/creativecommons
http://commons.wikimedia.org/wiki/Main_Page

SOUND EFFECTS

http://www.grsites.com/archive/sounds

WARNING: DON’T USE THE FOLLOWING SOURCES OF MATERIAL !!

1) Websites like TubeToolbox.com
DO NOT use websites such as tubetoolbox.com that claim to not violate YouTube Terms of Service. Unfortunately we know that they do, so please steer clear of them.

2) so called “Copyright-Free” Channels
Just don’t believe them until they send you a document signed by the original artist or their record label that YOU have permission to use their content for Commercial Purposes.

3) Free Downloads from for example iTunes or SoundCloud
Whilst it may seem logical that you could do this without getting into trouble, fact is that you simply are not allowed to re-upload music you have received through a “free download” without permission from the owner in writing.