One word: Wow.
I think from this point forward I will probably be buying ALL of my music at Amazon. Go check it out for yourself! They have an amazing amount of (100% legal) FREE music, as well as a ton of inexpensive classical music. It's a great way to build your music library!
Case in point:
Then, try searching "Classical," and sort the results by price. There's even a ton of FREE stuff! You may have to click around, but I was able to download several free jazz samplers, as well as some music from around the world this afternoon!