Getting the best music on the internet?

When I go on the internet to look for music, I look from individual
files to full torrents, but I know very little about the range of
quality of digital music.

I really want to know how to get the best out of my music downloading
experience, so I want to know what to look for. Some terms I hear
tossed around are "bitrate" and "lossy"

I know that some file formats are better than others, and that mp3s
degrade over time, but I don't know what ID3 tags are.

If there is anything you have learned about digital, downloadable
music that you think would be helpful, please share. I would very much
appreciate it.