I have bought a lot and sold a lot of cds on Amazon and Half.com. As long as you check the ratings of the seller (easier on Amazon, but prices are often lower on half.com) you should be okay - in my experience.

I used to live in Newton, NH - near Plaistow and Haverhill Mass - so I know what you are talking about. I used to take the train down to Kenmore Square in Boston to hit the used cd stores there.

Now I live a five minute walk from a used cd store and there are about three more within easy walking distance - but I buy most of my cds on line.

M22s, QS4s, M2 center, Hsu stf-1.