Don't buy music controlled by the RIAA. Just don't. The only way to stop them is to starve them. They're major campaign contributors, so the law will never be on our side until they're gone.
And by the way, don't download said music from sharing sites or friends. Artists need to see that we won't pay them any attention, with wallets or ears, if they associate with known extortionists.
Figuring out which labels are and are not RIAA affiliated has become more difficult in recent years. My former go-to place for this information, riaa radar, no longer exists, and the RIAA members page (http://riaa.com/aboutus.php?content_selector=aboutus_members) is of questionable accuracy.
For example, until recently Matador records was listed as a member. I emailed Matador and they basically told me that RIAA keeps re-listing them without permission. I don't follow the music industry closely enough to know which other labels are mis-listed as RIAA members, but I'm certain the number is non-zero.
And by the way, don't download said music from sharing sites or friends. Artists need to see that we won't pay them any attention, with wallets or ears, if they associate with known extortionists.