What's a Good Way to Buy Music Collections?

Someone offering large collections on thumb drives or other storage devices is probably illegally selling music without royalties being paid to artists and publishers.

If the seller of a large collection of music that was ripped from CDs also delivered the CDs to the buyer of the collection that would be fine.  But, if the seller makes multiple copies of what was ripped, that is a copyright violation.  It is "fair use" to take your personal collection and convert it to another medium for your own use, but, you cannot sell or even give away that converted collection.  If I made copies by ripping and I gave away the CDs that were copied, that would be a violation too. 

If I did not did not give away or sell that collection and the recipient wants that music, that person would have to buy that music and that is fair for the artist or the owner of the copyright.

Even if you bought the physical CDs of someone who has ripped his collection to a hard drive, that would still be a copyright violation.  The person buying the CD has a right to the use of the content on the CD, including ripping it to a hard drive for his own convenience.  But, when he sells the CD, he would have to delete the files associated with the sold CDs to be compliant.  It is simple--there was only one purchase of the right to the content, there cannot now be two different owners of the right to use the content unless there is a second purchase of the right from the holder of the copyright.