Comicbookrealm

Another price crawler - though this one also has a feature that allows you to add your own collection on your account, which then tracks its overall value. The upside to this is that it's a great free tool for getting an overview of your collection, though value wise when using it specifically for this feature is a million miles off.

In terms of valuing a comic book, the information provided is in depth, and it has a lot of visuals showing a lot of different (sometimes unnecessary) stuff.

Having re-visited the website whilst writing this - I've noticed that they've added a pretty good new feature. it appears that using CBR you are now able to search by CGC certificate number, to check specific values, which is extremely handy.

Pros

- Easy to use

- Easy to understand

- Free

Cons

- Inaccurate sometimes for the UK market

- Collection values are off, by a lot

- Cluttered, lots of ads.

Check them out here