Poliwhirl (Pokemon #061) is made with an old cd, frozen juice can lid or a margarine container lid, a printer, a piece of paper, some crayons, scissors, and glue.  I always prefer to use a heavy paper (like construction paper), but it isn't necessary.  (You could also use a circle of cardboard or bristle board).

The templates were originally made for a CD (which is 4.75 inches in diameter), but anything that's round and about the same size works... Make sure you ask an adult before you start gluing things to CD's!! 

Template for a color printer

Template for black & white printer