I just read an item from someone complaining about the dodgy copy CD's she bought.
As we all know it's largely speaking illegal (I wonder that ebay UK tolerates it so much, no other ebay site does).
My experience is that this illegality is unfortutanely mirrored in the behaviour of a disproportionately high percentage of ebay sellers of copies (that is, they never arrive, or if they do they are shoddy and don't work and the seller is hiding behind a false postal address and there is no way you can get an exchange).
As an example of the latter type - a prolific seller of Likely Lads copies who even claims to be the official representative of the Fan Club and therefore allowed to sell copies!
My advice - don't buy cd copies unless you are willing to take this substantially higher risk. Don't buy copies of copy-protected DVD's - it's illegal.
If you return something, always send it registered ("Signed-for"). I lost a lot of money because I didn't, and the Likely Lads seller claimed he had never received the return.