You know how an inexpensive gift can look fabulous if you package it beautifully? 
The same is true with centerpieces. Because I have the opportunity to do several centerpieces a year on a very tight budget I've figured out ways to make a single flower look almost as good as a full bouquet.
First start with the vase. You've likely seen these hurricanes around blogland. They're made from a dollar store candlestick and vase. 
Glue the two using a strong adhesive. I've made two sets of these using different sizes of vases.
Next, use an inexpensive filler which can also be purchased at the dollar store. Rocks, marbles, sea glass, all give added visual interest to a bouquet without a lot of added cash. The filler also helps anchor the flower so that one flower doesn't look so lonely. 
It's also good to use a flower with a larger head like a spider mum.
Finish off the arrangement by adding interest to the outside of the vase. I wanted this centerpiece to have a masculine vibe so I wrapped the vase with wide ribbon tied with twine. I sat the whole thing on top of a small mirror and a piece of hardboard (from the building supply section).
It's all in the packaging!
