[trebleshot]

Well, besides Evil Bay, there's Collector Action Figures. You have to register with the site in order to see price listings, but it's free and they cover a wide range of toy lines.

You could also hit up the bookstore/comic shop for Toyfare and the like. They may not always list the collections you're interested in and their pricing may be off in some cases, but at the very least it may give you some numbers to work with.

Any other Arkers care to chime in on this?