Images and music can be obtained for use when creating projects etc online for free as long as they come under the Creative Commons licence. There are four 'conditions' under the Creative Commons licence - Attribution (where users must make attribution to the original author), Share Alike (allows users to edit and remix works), Non-Commercial (users must not use images/music for commercial purposes) and No Derivative Works (where users can only use the original works).
For music, there is a website called Incompetech which has masses of royalty free music that users can use for their projects. The creator of the site only asks that he is given credit for any music that a person chooses to use under the Creative Commons licence. I won't upload a piece of music onto the blog, but if you are searching for music for something you are working on, have a look at the Incompetech site.
As for images, flickr, is not only a place where you can store your images, but you can search for images that fall under the Creative Commons licence. This makes finding images for your given purpose an easier task as you have 'permission' to use them - as long as you give credit where credit is due!