Grutlang does not sell anything. However, he is always willing to purchase any items that you may no longer want.
Outside The River Guild Emporiums, this is the best place to sell your accumulated wealth of game items up to 70% of their true value, up to a maximum of 600 gold. Better items should not be sold here. See Item Selling Guide for values and more information of other places that can offer more for better quality items.