When I was pirating music years ago (pre-Spotify era) I used to get .flac files from torrent sites, including Bon Jovi. I am sure some of them are still there.

However, the easiest path is if you have the original CDs is to rip it yourself (this will allow to chose .flac as a format with the highest quality possible). AIMP Audio Converter is my favorite application for that and it's free.

That being said, for my amateur ears I could not tell that much of a difference between a sound of .flac and a high-bitrate and properly ripped .mp3 file.