I've been using WWW.EMUSIC.COM for over 2 years, and have been happy overall with the cost and selection. I pay 40 cents per track and about $5 for most discs. Files are MP3s without any digital rights management protection.
Among the offerings, are all(?) the Skaggs Family Records and Grisman's Acoustic Disc.
NOW THE BAD NEWS: I have NEVER worked with an e-commerce site that has resulted in SO much unwanted e-mail SPAM. I used a unique e-mail address to sign up with e-music, and thank goodness, because either their security measures are faulty, or they sell e-mails to the UGLIEST kinds of spammers. Literally hundreds and hundreds of bogus drug offers, sex services, and scams have come in to that address. Since there has NEVER been a useful e-mail from the company -- and they have never responded to customer service inquiries about SPAM problems -- it all goes into the garbage.
But still. It makes me wonder how trustworthy their security is with my credit card info.