There is nothing wrong with buying used CD's. The real fault is in whoever sold that CD to half.com. How in the world does a gold stamp prove price exceeds value?

Records aren't cost free to promote or record. Just because you are denying the artist 3% rather than 50% doesn't really make a difference. You are in no way supporting an artist. CD's are actually about the price there were when they first caught on over 10 years ago.