This simple anemometer teaches how wind speed can be measured using a force balance. As wind displaces the ping pong ball, the angle measured from the built-in protractor can be converted into wind speed using the conversion table here: 

https://4-h.org/wp-content/uploads/2016/02/1-MeasuringWindSpeed.pdf

or here:

https://www.education.com/science-fair/article/earth-science_building-anemometer/#:~:text=Anemometers%20are%20apparatuses%20used%20to,Mayans%20and%20some%20Asian%20cultures).

https://www.researchgate.net/publication/231060194_Constructing_a_plastic_bottle_wind_turbine_as_a_practical_aid_for_learning_about_using_wind_energy_to_generate_electricity 

 Total cost for print material is ~$10. I have not found commercial equivalents for sale.