The value of old comic books is measured by the rarity and condition of the book as appraised by several online comic book dealers such as Sell My Comic Books. Comic book titles have numbers associated with them, along with a grading scale. The number and grade are used by appraisers to calculate the sale value of the book.
Comic book collectors can go online to several comic book selling sites, such as Sell My Comic Books or Comic Book Realm, and check their collection against a list of rare and collectible books.
To help in the evaluation of an appraisal, collectors can fill out an appraisal form online with the information requested about the book. The form is specific about the information required, such as the title, number and condition of the book. Sell My Comic Books requests photos of books requested to be appraised.
A grading scale is assigned to old and vintage comic books based on the popularity, scarcity and condition of the books. The grading scale goes from a low of 6.0 to a high of 9.9. Sell My Comic Books reports that the average sale price for comic books ranges from $50 a book to a high of $4,150.