Just as the name suggests, this site has free music, and of course, most are under Creative Commons. To find out which kind of CC it is—and if it’s available for commercial use—just click on the song title and then look at the far right column.
TakeTones has a really good library and you can use their music for free for non-commercial projects such as home videos and non-monetized YouTube content.
Although it would seem like a self-explanatory website name, you may have to pull out your wallet in some cases. You’re going to find mostly Creative Commons Attribution Required tracks here, but some are “CC-BY-NC”.