The tall balloon columns used as decorations at parties must be anchored with the proper base. Save money by making your own with a few inexpensive parts from your local home improvement store. Making your base also gives you more options.
Measure a corner of a piece of 3/4-inch thick plywood to a 12 inch square, or find a pre-cut 12-inch plywood square. Cut the square out with a circular saw. Measure diagonally from all four corners of the square and mark where they meet in the center with a pencil to find the exact center of the square.
Place a 1/2 inch metal pipe flange in the center of the plywood square and screw it into the wood with self-tapping 5/8 inch screws and a power drill with a screwdriver bit. Screw them all into the wood about half way. When you have them all in, screw each one in a little more, working across from one screw to the next until the tops of the screws are flush against the top of the flange.
Screw the threaded end of a 5 foot long PVC pipe into the metal flange, and you're ready to start building your balloon column.