I buy a lot of soundtracks, but really it all started with getting the free soundtracks during preorders (they don't do much of that anymore). I have picked up a game soundtrack or two that were from the same series of games but I only owned the first game.

My overall biggest complaint with game soundtracks that they are giving away currently is the ones that are only available for download. I'm such a collector that I hate not having a physical copy.