Damn if ony i had the extra cash 
My money is a bad connection going from the battery to the starter.I had this happen to both a Caprice and a Crown Vic.OR the battery may have a bad cell and is not taking charge.
BTW is this car still for sale ? If i don’t buy it i may know someoen who will.I’d REALLY hate to see it junked.The car looks to be in damn nice shape !