I doubt anyone has sold them; leastways not for 'hundreds'. However, they have acquired curiosity value as public ephemera, and thus undoubtedly they have some value. However, since Emin herself has said it isn't art, it won't ever fetch much.
It would certainly make for an interesting framed picture in a student flat, provided that a press clipping is shown alongside, and might acquire some value in future years, only provided that Emin's reputation lasts.
However, I've yet to see one of the posters - none of the newspaper reports I saw actually show one. Could it be a publicity stunt by Miss Emin? .... no, perish the thought.