A certain factory re-used packs that had a 1st edition stamp on them and covered it with a black triangle. Can't give you a number on the amount that are out there. I got one of each cover art for $11 each last summer when it was less known. They are rare but they don't exactly have a consistent value. If a single one sold tomorrow for $500 that would not make it worth that much. That would just mean that a single person felt it was worth it but that doesn't mean the rest of the market values it that high.