ROYALTY-FREE RESOURCES
There is not really any material you can use without at least considering copyright law. But there are resources available that are royalty-free media sites. Does that mean that royalty-free media are available free of cost? Not at all. Some royalty-free media are made available for free (but with use restrictions). Regardless of cost (or no cost) of the media users are bound by some terms of service or licence. Here are a few recommended sources to get you started (remember that crediting a resource is still necessary!):
