eBay has a great tool for gauging price on a specific item. If you search for something (in this case, Leatherman PST) and click "advanced" you will see a bunch of options, one of which says "sold listings" with a check box next to it. If you check this box, and then search, eBay will show you all listings that have sold that match your search, including the final price. I find its pretty useful for finding if a "buy now" price is off base as well...
Good luck with your sale mate!