Only one vehicle model sold for under $20,000 in July: The Mitsubishi Mirage.JOHN MURPHY PHOTOGRAPHY, John MurphyCar buyers have been through a whirlwind of low inventory and high prices in recent years.Even as prices improve, there was only one car model sold below $20,000 in July.But experts say the auto retail market might finally be stabilizing.It used to be relatively easy to find a vehicle under $20,000.