Yes. I looked in a dollar store just this afternoon. They had the same kind of cheap selection as the drugstores had--only one shade of purple. But they at least had both red and green! (Though the red was a crappy, pale kind of red, not as good as the red in the Staples pack).

I will at least look in a local art store. Maybe I can buy a sheet of green and a sheet of dark purple and go from there.