You can find a lot of amazing musicians in the Newgrounds Audio Portal (http://www.newgrounds.com/audio/), just be sure to contact them directly about using their music in commercial projects.
Q: Are video game sound effects covered by copyright laws? A: Yes. Even if some of the sound effects exist in the public domain, they are in the public domain because of copyright laws.
Are video game soundtracks royalty free?
Yes! In fact, you should only use royalty free music in games. Due to copyright laws and intricate royalty restrictions, using a copyrighted track in your game might cause legal issues or even significant fees. That is why you should always opt for using royalty free background music for games.
Why do video games use the '. ogg' file format for sounds so much? - Quora. , Composer & game audio specialist on 160+ titles since 1997.
Where do game developers get sound effects?
In short, most sound effects in games come from sound effect libraries, free or paid. Usually, the sounds in the libraries are sourced through real-life recording.