This is a Vertical Axis Wind Turbine which uses wind energy to drive things like an alternator/generator for producing electricity, or air and water pumps for cooling, irrigation and similar.
The turbine uses the 35-40% mechanically efficient Lenz2 lift+drag design. It is made almost entirely from scrap materials, and should cost about $15-$30 for the six vane version, which can be made by two people in four hours without much effort.