For small ticket items (<$25) if I want it, I just pay it. For everything else since I have been collecting over 40 years there really isn’t anything, I need but what I really enjoy is the fun of a little haggling; sometimes more than the item itself. If a seller allows me the privilege of a little lighthearted, respectful dickering I often am willing to buy multiple items. I always keep it respectful and if I sense that the seller isn’t into it I just politely say thanks and move on. Also I agree with the poster that said if someone (buyer or seller) starts talking about “book value” it is time to move along.