The 4" manual plastic rain gauge is available from the following retailers.  
Prices may vary.  Click here to read more about approved gauges for CoCoRaHS.

WeatherYourWay.com (the official CoCoRaHS gauge supplier)

Climalytic Instruments (manufacturer of the premium CoCoRaHS TROPO gauge)

Additional Suppliers

Ambient Weather

Best Buy

FLI Products

Forestry Suppliers

Scientific Sales

Tractor Supply Company

Weather Shack.com