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.
"This small crystal tree doubles as a wedding centerpiece & a table number stand." I'd put some of these around my house (minus the number) made with small branch pieces found in the yard and a string of beads.