It's impossible to give an exact value for a specific copy because its worth depends heavily on its condition, rarity, and provenance. However, here's a general idea:
* In pristine, graded condition (CGC 9.8 or higher), a copy of Marvel Mystery Comics #1 could be worth hundreds of thousands, or even millions, of dollars. A copy in this condition sold for over $1 million in 2014.
* In lower grades, the value can range from a few thousand dollars for a decent copy to hundreds of dollars for a very worn copy.
Important to note:
* Authenticity is crucial. Be wary of forgeries, and consult with reputable comic book experts.
* Condition matters tremendously. Even minor imperfections can significantly reduce a comic's value.
* Market fluctuations are common. The value of comics can change based on demand and other factors.
If you think you have a copy of Marvel Mystery Comics #1, it's recommended to consult with a professional comic book appraiser for a proper evaluation.