Remember Life Magazine--always had great images. Here are public domain images that your students can use without fear of copyright infringement. Some were published images and some were not. Images are separated by decades starting in 1860. Would be good for historical perspectives as well as today.
Creative Commons license chooser--answer the questions and this tool will suggest the correct choice. Creative Commons is a great resource for helping your students understand copyrighting as well.
Royalty Free Music--too often I have paid for music so that I don't break copyrighting. Here's a simple source for music with easy attribution. Recommend.