text: Ebay is the best answer since you'll find out how much the books ACTUALLY sell for, but it's often no good for single issues (a random issue of X-Men or Superman can fluctuate between 1.50 and 10.00 between listings unless it's traded particularly often because without a steady stream of buying and selling you'd dependant upon a few random buyers and just because I'm willing to pay $10 for one issue doesn't mean anyone else would.)\n\nhttp://www.comicspriceguide.com/ has individual issues, and you can also try any comic store website to see what they price it at.  Keep in mind that these prices are usually at a premium and not necessarily what you could expect to get if you, for instance, listed them on Ebay or sold at a convention.