The cold, hard truth of the matter is that your question is not relevant. ALL collectibles are ONLY worth what someone is willing to pay for them.
Valerie F makes a good point.
If you want to speak of 'theoretical' value consult something called the Overstreet Comic Book price Guide. Mind you, even if someone decides to BUY your comic book, they will no doubt only pay a percentage of what it is worth in theory.
Buy what you enjoy reading. Speculation in the last decade or two really screwed up the comic book market.