I use itumes (preview) to hear whether I like the music, and use the options of "Buyers used similar music" to find similar music. Then buy new CD's at amazon.co.uk which is very cheap at the moment.
I also use Ebay, but the wholesellers tend to use bubble envelopes which is insufficient protection for International shipment, shipping carton protect much better.
Favorite record companies are Telarc, Chesky, Verve but Chesky seems to boost the recordings