Help to find a website with pricings on graphic novels/comics and lithographs

A couple of years ago I acquired a collection of graphic novels/comics (some limited edition signed) and lithographs (again some signed limited edition).

These are now taking up room and wondered if anyone knows of a website available for pricing such items to see if they are worth selling.

Cheers in advance for any help that can be given .

check ebay for guidelines. unless you have a really rare comic with signature you might find they arent worth that much.