Source: dig.ccMixter Home
Trying to create multimedia without stepping on copyright issues can be difficult, but sites like digCCMixter make it easier.
To get started, head on over to digCCMixter and start looking for music that you want to use. When you find a song you like, click on the orange download button.
digCCMixter will show you exactly what you can do with the music and allow you to copy the artist information for attribution.
Click the big Download button to download the music, and the Copy to Clipboard button to save the artist information. The downloads are in MP3 format, which means you can use them in Google Slides presentations.
The site can be used without creating or requiring a user account.