While there have been comics featuring Muhammad Ali, and Superman has faced many opponents, there is no known comic book where these two characters have clashed.
It's important to note that comic book values vary greatly depending on several factors, including:
* Rarity: How many copies were printed.
* Condition: The physical state of the comic book.
* Popularity: How desirable the comic is to collectors.
If you have a specific comic book in mind, you can research its value on online marketplaces like eBay or ComicBookRealm.