This is one of the larger crawlers available for use.

Gocollect is extremely comprehensive, with great little features such as a weekly top ten list, determined by the increase of the book's value, abd speculative risers that have spiked over a short period. This is a free to use website, though they have a 'pro' feature which is paid. This allows you access to more information and other speciality features.

Another upside to Gocollect, is that it is not limited to just comic books, but anything deemed collectible. The obvious upside to this is that it makes the website more versatile as a tool, though the downside would be that their attention is more widespread, without the fine tuned focus on the collectible in question.

Pros

- Reliable and well known

- Much more modern vs a lot of websites in the industry

- More analytical with in depth data

- Free verison

- Versatile and not limited to comics

Cons

- As always, US based

- Pro features are a paid-for benefit

Check them out here