This site has Creative Commons (CC) licensed music. You have to give attribution, but they even generate the credit text for you. Just choose what you're using in the checklist.
http://incompetech.com/music/royalty-free/licenses/
On Soundcloud, you can search for music with a CC license. If this is for commercial use, make sure you use the appropriate filter on the left (probably "To modify commercially"). As with the above, you'll have to give attribution for the source.
https://soundcloud.com/search/sounds/?filter.license=to_share
Purple Planet might work for you, but read the license terms carefully. The free license won't work for all e-learning, even with attribution.
http://www.purple-planet.com/