I mean... I've always gone by the 1/3 guideline, which basically sets the value of a used item at 1/3 the cost of what it would be new. A person paying 1/2 for a used item means that the second buyer pays the exact same for a USED item that you, the original buyer, paid for the item NEW. I know I didn't word that right, so for example, say you bought a PC for $1,000 and resell it to me for $500. So for $500 you got a new PC, while for the same amount, I got a used one. Does that sound fair to you? That being said, it's worth as much as someone is willing to pay for it. Based on your comments, no one was willing to pay your asking price.