Building A Deck Pier Video
This is called the Form-Footer. This is a plastic system with all the various parts included. The rebar comes in the kit and is precut and everything just snaps together. Need more height? Just add another section to the form. This allows you to get the deck pier down below the frost line and above the ground.
A very interesting product, that sells for less then $100. Just dig the hole, drop in the assembled Form-Footer with all the rebar precut, and you are ready to pour concrete. One of the best footer devices I have seen. Wish I had these back when I was building decks!