Where do I find short vocal samples for my music?

[wavewar3]

I'm looking for vocals like https://www.youtube.com/watch?v=gzSp8kn6dys at 0:26 . Documentary-like I guess. I don't have much of a voice for this. Do I also have to ask permission to use vocals like this if I'm selling my music?

Knife party's 'centipede' is a great example as well

 

[wavewar3]

Also does this still apply to youtube videos? Did skrillex have to private message the cup stacking girl to use the audio in her video?