flowers from the farmers market! in a clamp closed glass jar (where i also store barley and rice sometimes) ...i love putting flowers in in something other than an ordinary vase, like a pitcher, jug or even interesting glasses and tumblers.
unless they are locally grown, flowers are not the most eco-friendly thing. they are usually grown overseas using lots of chemicals which wreak havoc on the (mostly young female) workers.... Love, Women and Flowers is a documentary that delves further into this subject, showing the hazardous labor conditions that women in the Colombian flower industry work in...definitely worth a watch.
it's nice to have flowers indoors, but you can easily reduce your carbon footprint (shipping the flowers from overseas stresses our resources!) by buying fresh cut flowers from your local farmers market or buying a potted plant for your home. ficus are one of my favorites... peace lilies and shrub roses are great potted flowers to try indoors too...livens up a room instantly!