I'm probably going to sound like a smartass but here goes anyway :D
There is a difference between buying a second hand good and downloading something from the internet for free - and it's not just the money;-) If you buy a cd in a second hand book shop or on ebay then you are buying a single item that involves a single monetary transaction as opposed to a downloadable file which can be downloaded an unlimited number of times by an unlimited number of people. Secondhand sales are also legal as they are mostly done within a system that involces VAT (value added tax) back to the local government and they are generally done through a shop or service that is licenced to do so. Just pointing out the difference BUT I do see where you are coming from!