HELP Me With Centerpiece Ideas!

Shelley,
You can buy that crystal stuff that when you add water it becomes soft and looks like clear jello (for lack of a better comparison). You can add food colouring, sparkles or whatever little things in it to make it shine. Then you could add some candles that would stand up straight in it (the jelly stuff is thick enough to hold it up) or put floating candles on top, or put flowers (real or fake) in them. The crystal stuff is inexpensive. You only need a little bit because when you add water they expand BIG TIME.

With 6 1/2" vases, it sounds like you are going to need some added height to bring more drama to your centerpieces. Fresh flowers are always a good option. For height, try calla lilies, dahlias, snapdragons, or larkspur. I have also seen beargrass used, as well as curly willow branches. If you use flowers that are large or vibrant enough, you won`t need as many, which cuts down on your cost.
Another good idea is to fill a vase with fresh lemons, limes, green apples, or other fruits. They don`t wilt, smell great, add lots of color, and are very inexpensive.