Welcome to the board :)
The Clinton Anderson "handy stick" isn't a lunge whip. A lunge whip is flexible through it's whole body and has a long string. The Clinton Anderson style stick is pretty thick and solid in its body and then has a string. I think the Parelli's call theirs a handy stick. The no-brand ones are called natural horsemanship training sticks. They're all the same thing, just in different colors!
If you google "natural horsemanship training stick" you will find cheaper alternatives.
* I'm often reading and posting from mobile and Siri loves to make a mockery of the English language.