These are centerpieces I made for my Brother and his Wife's 50th Birthday Party. I used my Cricut II, specialty scrapbooking papers, floral wire, a glue gun, some metal planters, and some balloon weights.
Balloon weights! Just cut an 8 inch square out of burlap and set a rock in the center. Pull up the corners and tie them together using bailing twine (ribbon would look nice too). Tie your balloons to it and ta-da! So cheap and easy!