Music and movies are very, very different. While there is no site I know of that provides purchase of DRM free downloads of popular movies, there are many alternatives for music. I purchase most of the music I like from Bandcamp and I think even Amazon allows purchase of DRM free downloadable music. I feel ZERO regrets about pirating movies, because I am not given any option worth purchasing, but I would feel bad pirating music and I think you should probably too, if you could afford it.