fully subjective, obviously.
There have been so many good scores and lower pricing over the last year or so, location can be a factor as well.
A decent to good pac cab, fully working is worth $300-$500 and probably more depending on condition.
one man's opinion
and for the record, I would only pay $200-$300, but I have become so diligent with watching craigslist, and my garage is so full, it has to be a good deal to get me interested.
My buddy on the other hand would pay $600 no prob for a nice pac.