What's the best way to download SINGLE songs?

I know this seems like a dumb question, but Googling it just brings up a YA thread telling you to use Google. I remember back in the day, I would use Limewire and get any song I wanted. Torrents are great for albums, but what do you do if you just want one song? I suppose you could download the torrent, and then uncheck every other song on the album before downloading, but that seems really inefficient.