I found cheap little blackbirds at the local Dollar Tree the other day.
They are in dire need of improvement, as the white styrofoam body form shows through the feathers and flocking in several spots.
I bought them all, (of course!) then Pup and I fixed them by dabbing automotive trim dye on the bad spots. I think black liquid shoe polish would work just as well and be cheaper, too. After we let them dry in the sun for a few hours they looked good enough perch in the graveyard.
So if you're looking to scare up a flock, check out the dollar stores!