Post model #'s and options either here or in the general forums and ask someone to price it all for you. Although I agree with the above poster, I'd never pay more than 50% of new for used gear. Search our classifieds also by model to see what they sold for recently.
Is it shop rental gear they're retiring? Personally I wouldn't be interested at any price. fwiw, most LDS's service used gear they sell first also.
Scubapro also recently started selling thru major online retailers so you might check leisurepro.com, scubatoys.com or scuba.com - all sell Scubapro with full warranty coverage. Contact [user]beaverdivers[/user] (Casey) also, he's a Scubapro Platinum dealer and has offered some excellent deals on new/lightly used SP gear here lately.