At the moment, there are 21 listings for 1 cobblestone in a row listed at $10,000,000. It's genuinely annoying for /ah to be flooded with listings that are obviously absurd, and it would be nice if there was some method to remove / report listings like this - but as far as I can tell, there's no *current* rule against it, outside of maybe the "common sense" stuff, idk. But imo, this constitutes spam.
This shouldn't be happening, Use common sense, and don't list items for extreme values. They've all been removed.