Does your "deal value" takes into account any detail beside the asking price?
There are many vehicle offered for sale with seemingly great prices, which you grade as "great deal." However, some of these vehicle are having rebuilt title (salvage) and those are never great deals.
Here's an example:
http://www.cargurus.com/Cars/inventorylisting/viewDetailsFilterViewInventoryListing.action?entitySelectingHelper.selectedEntity=d373&radius=500&zip=40031&sourceContext=requestedNewsletter-ContactDealerForm-locationSubject_false_2949708&trimNames=NONE_NONE&colors=NONE_NONE&sntEmlId=20543119#listing=44056374