Are you looking for karaoke/instrumental versions of songs, because if you are you're most likely gonna have to pay for it. I would try messaging a few users on Youtube and ask if you can have a mp3 downloadable version to use.
Theres a website that you can download youtube videos into audio. Look up like 'youtube video converter' or something. And you would be looking for the Acoustic version, Or Instramental.
On youtube just type in the song you want but put karaoke aafter it like this - Billy talent karaoke. And you will get lots of results. Its free, and its good.