Rhobert Dail Meilyr is a Market Price Guide of the herb prices. He is located at the Grand Exchange in the Tower of Voices in Prifddinas, south of the entrance to the south-eastern balcony that contains the crystal tree patch. He is able to decant potions into any dose. He is the brother of Rhodri Dail, and also a member of the Meilyr Clan. He is a counterpart to Bob Barter at the Grand Exchange in Varrock.
If right clicked he can show you the current market price of popular herbs. The herbs listed are: