The Mercinaean Magic Stall is currently extremely well stocked with runes and the odd potion (shortage of glass restricts our potion stock) and at the time of writing, the cheapest in Avalon.
The Stall can be found at East of Cassiandora Square, ie, N of the Grassy Knoll (dodge those Presidential Assasins at that location!).
Remember to mail me if you want charged amulets/rings etc and if you have any spare potion bottles (50gp money back). In order to fully stock the stall with potions I need your empty bottles !