Get artsy and frame your bouquet. Start by hanging flowers upside down. Once they're dry (two weeks or so later), pluck the petals and arrange them inside a shadow-box frame; use a glue gun to attach them. Keep your creation in a shady spot so its color will last.
Let your guests know that they're welcome to take home centerpieces and bouquets. Place a special card at each table saying as much at the end of the night. Or ask your florist to redistribute day-old buds to local nursing homes, assisted-living communities, or hospitals.
Split the cost of flowers with another bride. Ask the venue manager if a wedding is happening the day after yours and if that bride would care to share arrangements. It's most likely you'll get half off ceremony flowers, as they tend to be more versatile, but you never know.