Intended User: People with a backyard and a tree. 
Advantage:  Cheapest Yet
Disadvantage:  As the design is it may swing around too much when hit. 

Great design from Jeff Johnson.  Here is his link

Cut up the tire as needed with a serrated knife.   Attach the two tires with the cable as show.  

Parts List: 
Small Car tire 2 required

Some cable, rope, galvanized sheet metal screws.

Dowel or waster.

Reinforce and wrap the "hand" around the stick by attaching the fold with sheet metal screws or bolts. It can be hung on a cable between two trees. Look for a dog-run cable kit at the hardware stores & it has all of the hardware you need