The Briggs and Stratton Flyer, also known as the Smith Flyer, is listed as the cheapest car of all time, costing US$125 in 1922 ($1910 today).
The Flyer has 5 wheels, of which 1 is driven by a small petrol engine. The main body of the car consists of 6 wooden slats, to which the mechanical components are attached. To drive, you start the engine with it raised into the air, and then lower it to the ground using a lever.
In Car Crushers 2, I see the Briggs and Stratton Flyer being very-early game due to its low speed and weight. The car would have the lowest part count in the game, as well as abysmal attack and defense stats.
Specifications:
Length: 98 inches (249 cm)
Wheelbase: 62 inches (157.5 cm)
Width: 30 inches (76 cm)
Wheel size: 20 inches (51 cm)
Power: 2 hp
Top speed: 25 mph (40 km/h)