StashMyComics.com
Keep track of your comic book collection online with full comic details, cover images, and current market values. Run reports on your collection. Enter to win prizes and giveaways. Did we mention its FREE!
https://www.stashmycomics.com/default.asp
Lyria: Comic Book Exchange
Arts, Comics, Resources, Collecting - Lyria: Comic Book Exchange. Tracks comic book prices in stock market format.
https://www.lyriacomicexchange.com/
Nostomania
Arts, Comics, Resources, Collecting - Nostomania. Free online comic book collection, wantlist, and sales inventory tracking.
https://nostomania.com/