Does anyone know where to get price data for older comics?

I run a tiny startup that lets you organize and track info about your comic book collection.
I would like to add price data to the comics in the database. I think
this would be a great feature for collectors to see how
much their collection is worth.

I contacted http://comics.gpanalysis.com but they don't resell their data,
and I contacted Overstreet price guide but they don't resell their data either.

The only option I can see is doing my own data mining on eBay and other online
auction houses.

Does anyone know of any other place I can get this data?

You might talk to Jonathan Land - He is the owner of http://www.boompanda.com/ a successful ecommerce site for comics. Not sure if he is into the vintage stuff, but I know him from Google+ - he is a nice guy and I'm sure could point you in the right direction: http://goo.gl/4sFKo

I did a bit of asking around and you should supposedly be able to get some pricing in the "
the Overstreet Comic Book Price Guide"

"The Overstreet Comic Book Price Guide" Links:

http://www.gemstonepub.com/archive/06_cbpg.asp http://en.wikipedia.org/wiki/Overstreet_Comic_Book_Price_Guide

Additional Resources that may be helpful:
http://www.comicspriceguide.com/ http://comicbookrealm.com/
http://www.metropolisplus.com/COMICSBASICS.htm If I were you, I would focus on creating an add-on to your portal where comic books can be traded. Perhaps also look into the idea of having your present users rate and evaluate each other's comic book collections.

Good luck with your venture.