It is always helpful to be informed about the value of particular dispensers. Price guides are a great way to get a general idea of the prices for particular pieces! LaSpina's Price guide is up to date as it is reissued each year and it is a great way to keep track of your collection as it has check boxes to make notes of your pez. Peterson's guide is full of pictures to help you identify your pez and determine which version of Mickey Mouse or Donald duck you have! Warman's guide is perfect for carrying with you to have quick and easy access to a price guide with pictures! These are for sale here.