1) I have bought music beCAUSE I discovered it online.
2) CDs are incredibly cheap to mass produce, and the machinery for making them has long since been amortized, yet the companies are still charging $10 to $20 for 'em (the artist gets a small cut).
3) The powers of the industry have got Congress to extend copyrights well beyond a good societal norm in order to enable them to lock in future profits with capital.
4) mp3's are not the equivalent of CD tracks.

Fight the power. Boycott the members of RIAA.
Listen to live music. Pay real people. Buy CDs at performance venues.

I like old Radio Shows, Goons, ISIRTA, ISIHAC, Navy Lark, Dad's Army, Suspense, CBS Radio Mystery. I may download a top 40 to give it a listen and a toss, but if I'm regularly listening to something I've downloaded, I'll buy it. That's what happned with Austin Lounge Lizards and Fiery Furnaces.

I used to use Kazaa, they included a lot of garbage sales stuff with their program, ultimately I bought into limewire and have been happy with it.