Instructions
Examine your Marvel comics for any obvious signs of diminished value. Check the date of the Marvel comic book's release. Ensure that the copy you have is an original copy and not a reprint. The older the comic is, the more likely it will be valuable. Carefully inspect the physical condition of the comic book for damage. Any tears, folds, missing covers or other types of damage that the comic has endured will significantly diminish the value of the comic.
Grade the Marvel professionally if there is no obvious damage to the comic. Professional graders will give their expert opinion on the condition of the Marvel comic. It is possible that a professional grader will detect indicators of value that you would not have otherwise. Comic graders will rate the contents of your collection between poor and mint condition. Having a record of an expert opinion on the condition of your comic takes away any doubt potential buyers may have about the comic.
Perform a search for your Marvel comics books on an online appraiser like Comic Price Guide or My Comic Shop. Consult print magazines that address comic values like Wizard Magazine or Overstreet. Take your Marvel comics to several comic stores to see what value estimates you receive. Get several opinions before you decide to sell anything. Take the recording of your professional comic grade to ensure potential buyers that the comics are in good condition.
Search for your comic on auction sites like Ebay to see the asking price of other sellers. Ebay prices are not necessarily professionally set, but they do give an idea of what the general masses are paying for certain comic issues.