Heralds are a great collectible that can give enthusiasts art from their favorite films at a fraction of the cost of a One Sheet. Though you find heralds mostly from Spain, there were some produced in the US and other countries.
Heralds are small newsprint flyers that vary in size from 3" x 5" to 6" x 9" (and everything in between). They are often printed on both sides, with the flip side often displaying information about the local theater. Heralds can be just a single page, or a folded over 'booklet' of several pages. Bought in groups of thousands by theater owners, they were given away all over town in advance of the film's opening. They were printed as early as the 1910s up to the early 1980s.