If any of the above posts weren't really clear, I'll try to help explain it.
On RuneScape, ingame, join the friends chat "R Quark." They price every single rare in that fc; Masks, Edibles, Phats, etc. You basically go in there and say ask "red phat?" Then someone will respond with something like 1209b or 1206s.
If it has a "b" that means this is the price the item will AUTOBUY at. If it has a "s" that means its the price the item will AUTOSELL at.
There is really no point to this, as to find the accurate prices you need to join r quark and would need to update this page every hour or so, when the r quark clan already does it on the forums.