I have often used eBay to find what I call a "real-time value" for a comic book, in other words, what that comic is going for right now and what you can expect to get if you sell a similar item. Sites like Comic Seeker have gone a step further, giving you the capability to search through many different sites for a comic. These are great resources for the collector and having these kinds of tools will only aide you in selling and buying comic books.
I recently got an email from another company - Terapeak. They do market research data on eBay auctions and offer a plethora of information about the trends of what a superhero is selling for. The first site they sent me to was their superhero widget that shows information on certain superheroes. The main widget in the center wasn't working and I tried it in Firefox and Chrome. The search function at the bottom however, did work.
The real jewel was in clicking one of the comics on the side of the main widget. That took me to the main Terapeak site (this link takes you to a Batman query) where you can run a search about a character on eBay. You can search the last 14 days of listings as well as the last 90 days of purchases if you sign up (it does cost $24.95 a month) but you can search up to 8 days for free. You can see when items of that character were listed, what day, what type, if they used special features, duration, keywords, etc. There is a TON of information that any serious buyer or seller can use to make decisions about their collections. It is a very neat tool that could aide you in your endeavors. I dug a little and Terapeak was one of the first companies to do data licensing from eBay and have grown from a startup company to a worldwide endeavor. They state that people who use Terapeak earn 30% more than people who don't. The cost seems high for everyday sellers, but for serious buyers or sellers, it could be a very useful tool.
