I get several requests about the value of Treasury Edition comic books and I found a great source for information for you.
Treasury Edition comic books are large format with square bindings, typically reprinting material found in more traditional format comics. The most common sizes are 10″x13″ and 10″x15″. The format started in the 1930’s, but I’m usually asked about the treasury editions from 1970’s to early 1980’s, usually DC or Marvel (especially Marvel Star Wars). I have to warn you, these comics aren’t value gold mines, but there are collectors out there. You can find copies for sale on E-bay from a few dollars to the $10 to $20 range.
The most complete site I’ve found is treasurycomics.com. Webmaster Rob Kelly has put together an amazing amount of information on these comics and if you want to know more I highly recommend his site.