Paper lanterns as light-up centerpieces--inexpensive idea. Slip a Vase in the middle of each lantern and add flowers of choice. OR just adhere silk flowers to top edge of lantern.Put BATTERY OPERATED CANDLES/lighting inside and around each lantern.
Submerged Calla Lilly Centerpieces: I could also show you a couple of pieces with water pearls that might be a good idea. This is simple and elegant. I LOVE THIS CAN ONE OF YOU DO THIS? with purple calla lilies and white candles