Being a relatively newbie, I need guidance. I have a chance to buy a small collection. I also have to sell some of my extras,and some of the extras in his collection. According to the prices in the price guide,how much should I be able to sell or buy the extras? Is there a percentage I should try to work on? I dont want to cheat the seller,and I dont want to overpay.Thanks for any help.Confused,Dick