There are platforms where you can license music for a fee, including MANY platforms where you pay a monthly subscription fee for variably numbered or unlimited downloads from their music library (without further royalties).
There are also some legitimate places to get interesting music with neither a subscription nor a royalty.
Here are a few.
RIGHT WITHIN YOUR VIDEO EDITOR!
I use the Filmora video editor (which is around $80). Click on the tab AUDIO for downloadable music tracks. While Filmora tucks a few paid add-on options inside its software, so far, the music files I've liked have been entirely free. Pretty wide selection.
YOUTUBE AUDIO LIBRARY
This is so huge it almost dwarfs mentioning anything else. As of late 2021, it shows about 2000 screens of 100 each, or 200,000 tracks. When you are skimming, you can star things as favorites.
https://studio.youtube.com/channel/UCQFeWyTpzYGJbYc1vXg7GZQ/music
PIXABAY / MUSIC
Pixabay has a wide range of royalty-free video clips, images, and - Music! "Joining" is free - email registration - and soundtracks offer a chance to make a donation to the creator and request you include a credit for the source.
There are many thousands of tracks in diverse genres. There are several dozen genres ("smooth jazz," "cartoons.") (Be careful not to accidentally click on more than one genre at once, you may hit a null combination). Each soundtrack shows a volume profile.
Pixabay has it all: Video, photo images, and music. For video & stills, see also Unsplash and Pexels. (For the giant library of pay-for-use footage, see Shutterstock.)
Specialty Sources
INCOMPETECH / Kevin MacLeod
I like Andrew Bossom and his Rewboss YouTube channel, and he likes Kevin MacLeod music tracks. These are free to use; BUT acknowledgement required in your show notes. MacLeod has a Wikipedia page here.
AUDIONAUTIX / Jason Shaw
Similar to Kevin MacLeod's model. A wide variety of music, free to use, acknowledgement required, at the link below. Jason's music also shows up on some sites that use a monthly license model.
Creative Commons / List of Sites
Creative Commons has a webpage for music licenses, and notes that Creative Commons licenses may vary (some may require "no derivative works," for example. They provide a list and links to a dozen websites that offer music under the Creative Commons paradigm. The sites they link to may have a variety of licensing and usage rules, so read the fine print.
See for example:
Read any music website carefully for it rules; don't get caught with issues like "Content ID" warnings (here).
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Although it's off topic, let me mention here that two ways to get inexpensive freelance design help (for example, for animated YouTube brand intro's) are FIVERR and UPWORK and FREELANCER. I think FIVERR is mostly offshore; UPWORK seems to be U.S. See some video intro's for my brand on YouTube, from Fiverr, here.
