The Red book, PCGS grading prices, your local coin dealer, coin shows, Ebay asking and sold prices, are just a guideline, and will all have different prices depending on many aspects of a coin. The actual grade, the type of wear and damage, the quality of the strike, toning or corrosion, and the general appearance and attractiveness of the coin play a big part in what it's worth. You get a "Jekyll and Hyde" coin where one side grades higher than the other, and you get another variable in grading and price.
