you can get the vases at Dollar Tree, 3 bags of rocks and the floating candles in a 6 pack at Hob Lob. With a super gorgeous orchid as the flower, in the colors of the wedding, you've got yourself a very pretty, and very thrifty centerpiece!
Jello in a vase and drop flowers in it. Use half the water that jello recipe calls for for more vibrant color. you could use lots of different colors, use lots of stuff to toss in there and use them as centerpieces for any party!
Beautiful center pieces or just around the house- rocks, flower of your choice (maybe string it to a rock by the stem so it doesn't float) in a vase, fill with water, add small candle and voila-on the mantle?