I hit the Farmer's Market in Santa Monica every Saturday, partly because I'm headed to McCabes and Vidiots anyway, and partly because of the flowers. Get there late enough and one of the vendors cuts his prices almost in half.
You take your chances, of course, that the great colors and varieties are sold out, but even when it's down to daisies, dahlias and hybrid roses, you can fill every vase in the house. This last time, the guy told me submerging the stems for an hour or two makes the blooms last longer.
Did it work? Not really. But these colors in that big sink sure did look nice, so I shot a bunch of photos.