diff --git a/cache.lua b/cache.lua
index 89bb60e..a97c6f3 100644
--- a/cache.lua
+++ b/cache.lua
@@ -63,12 +63,12 @@ function public.item_id(item_name)
 end
 
 function private.scan_merchant()
-	Aux.util.loop_inventory(function(bag, slot)
-		local item_info = Aux.info.container_item(bag, slot)
+	for slot in Aux.util.inventory() do
+		local item_info = Aux.info.container_item(unpack(slot))
 		if item_info then
 			aux_merchant_sell[item_info.item_id] = item_info.tooltip.money / item_info.aux_quantity
 		end
-	end)
+	end
 
 	-- TODO maybe more detail? zone or  local merchant_name = UnitName('npc')
 	local merchant_item_count = GetMerchantNumItems()
diff --git a/core.lua b/core.lua
index 6716c79..db2652a 100644
--- a/core.lua
+++ b/core.lua
@@ -1,5 +1,5 @@
 Aux = {
-    version = '2.9.17',
+    version = '2.9.18',
     blizzard_ui_shown = false,
 	orig = {},
 }
diff --git a/post.lua b/post.lua
index e3c2dbc..fa92c5c 100644
--- a/post.lua
+++ b/post.lua
@@ -9,52 +9,54 @@ function private.process()
 			state.allow_partial = false
 		end
 
-		local stacking_complete
-		local stack_slot
-		
+		local stacking_complete, target_slot
+
 		Aux.stack.start(
 			state.item_key,
 			state.stack_size,
 			function(slot)
 				stacking_complete = true
-				stack_slot = slot
+				target_slot = slot
 			end
 		)
 
-		Aux.control.wait_until(function() return stacking_complete end, function()
-
-			if stack_slot and Aux.info.container_item(stack_slot.bag, stack_slot.bag_slot).aux_quantity <= state.stack_size then
-				private.post_auction(stack_slot, function(stack_size)
-					if state.posted == state.count then
-						state.partial_stack = stack_size
-					end
-					state.posted = state.posted + 1
-					return private.process()
-				end)
+		return Aux.control.wait_until(function() return stacking_complete end, function()
+			if target_slot then
+				return private.post_auction(target_slot, state.posted == state.count, private.process)
 			else
 				return public.stop()
 			end
-
 		end)
+	end
+
+	return public.stop()
+end
+
+function private.post_auction(slot, partial, k)
+	local item_info = Aux.info.container_item(unpack(slot))
+	if item_info.item_key == state.item_key and Aux.info.auctionable(item_info.tooltip) and (item_info.aux_quantity == state.stack_size or partial and item_info.aux_quantity < state.stack_size) then
+
+		ClearCursor()
+		ClickAuctionSellItemButton()
+		ClearCursor()
+		PickupContainerItem(unpack(slot))
+		ClickAuctionSellItemButton()
+		ClearCursor()
+
+		StartAuction(max(1, Aux.round(state.unit_start_price * item_info.aux_quantity)), Aux.round(state.unit_buyout_price * item_info.aux_quantity), state.duration)
+		Aux.control.wait_until(function() return not GetContainerItemInfo(unpack(slot)) end, function()
+			if state.posted == state.count then
+				state.partial_stack = item_info.aux_quantity
+			end
+			state.posted = state.posted + 1
+			return k()
+		end)
+
 	else
 		return public.stop()
 	end
 end
 
-function private.post_auction(slot, k)
-	ClearCursor()
-	ClickAuctionSellItemButton()
-	ClearCursor()
-	PickupContainerItem(slot.bag, slot.bag_slot)
-	ClickAuctionSellItemButton()
-	ClearCursor()
-	local stack_size = Aux.info.container_item(slot.bag, slot.bag_slot).aux_quantity
-	StartAuction(max(1, Aux.round(state.unit_start_price * stack_size)), Aux.round(state.unit_buyout_price * stack_size), state.duration)
-	Aux.control.wait_until(function() return not GetContainerItemInfo(slot.bag, slot.bag_slot) end, function()
-		return k(stack_size)
-	end)
-end
-
 function public.stop()
 	if state then
 		Aux.control.kill_thread(state.thread_id)
diff --git a/post_frame.lua b/post_frame.lua
index 1c2735a..f7551a9 100644
--- a/post_frame.lua
+++ b/post_frame.lua
@@ -747,20 +747,15 @@ function private.quantity_update()
 end
 
 function private.unit_vendor_price(item_key)
-    local inventory_iterator = Aux.util.inventory_iterator()
 
-    while true do
-        local slot = inventory_iterator()
-        if not slot then
-            break
-        end
+    for slot in Aux.util.inventory() do
 
-        local item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
+        local item_info = Aux.info.container_item(unpack(slot))
         if item_info and item_info.item_key == item_key then
 
             if Aux.info.auctionable(item_info.tooltip, nil, item_info.lootable) then
                 ClearCursor()
-                PickupContainerItem(slot.bag, slot.bag_slot)
+                PickupContainerItem(unpack(slot))
                 ClickAuctionSellItemButton()
                 local auction_sell_item = Aux.info.auction_sell_item()
                 ClearCursor()
@@ -828,14 +823,9 @@ function private.update_inventory_records()
 
     local auction_candidate_map = {}
 
-    local inventory_iterator = Aux.util.inventory_iterator()
-    while true do
-        local slot = inventory_iterator()
-        if not slot then
-            break
-        end
+    for slot in Aux.util.inventory() do
 
-        local item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
+        local item_info = Aux.info.container_item(unpack(slot))
         if item_info then
             local charge_class = item_info.charges or 0
 
diff --git a/scan.lua b/scan.lua
index c31f60e..392fbe6 100644
--- a/scan.lua
+++ b/scan.lua
@@ -231,8 +231,8 @@ function private.submit_query(k)
             private.wait_for_results(function()
                 local _, total_count = GetNumAuctionItems(private.current_thread().params.type)
                 private.current_thread().total_pages = math.ceil(total_count / PAGE_SIZE)
-                if private.current_thread().total_pages >= private.current_thread().page + 1 then
-                    private.wait_for_callback(private.current_thread().params.on_page_loaded, private.current_thread().page, private.current_thread().total_pages, function()
+                if max(1, private.current_thread().total_pages) >= private.current_thread().page + 1 then
+                    private.wait_for_callback(private.current_thread().params.on_page_loaded, private.current_thread().page, max(1, private.current_thread().total_pages), function()
                         return k()
                     end)
                 else
diff --git a/stack.lua b/stack.lua
index e41de79..505a9ab 100644
--- a/stack.lua
+++ b/stack.lua
@@ -3,95 +3,103 @@ Aux.stack = public
 
 local state
 
-function private.item_slots(item_key)
-	local slots = Aux.util.inventory_iterator()
-	return function()
-        local slot
-		repeat
-			slot = slots()
-		until slot == nil or private.item_key(slot) == item_key
-		return slot
-	end
+function private.stack_size(slot)
+    local container_item_info = Aux.info.container_item(unpack(slot))
+    return container_item_info and container_item_info.count or 0
 end
 
-function private.find_empty_slot()
-	for slot in Aux.util.inventory_iterator() do
-		if not GetContainerItemInfo(slot.bag, slot.bag_slot) then
+function private.charges(slot)
+    local container_item_info = Aux.info.container_item(unpack(slot))
+	return container_item_info and container_item_info.charges
+end
+
+function private.max_stack(slot)
+	local container_item_info = Aux.info.container_item(unpack(slot))
+	return container_item_info and container_item_info.max_stack
+end
+
+function private.locked(slot)
+	local container_item_info = Aux.info.container_item(unpack(slot))
+	return container_item_info and container_item_info.locked
+end
+
+function private.find_item_slot(partial)
+	for slot in Aux.util.inventory() do
+		if private.matching_item(slot, partial) and not Aux.util.table_eq(slot, state.target_slot) then
 			return slot
 		end
 	end
 end
 
-function private.find_charges_item_slot(item_key, charges)
-	for slot in private.item_slots(item_key) do
-		if private.item_charges(slot) == charges then
+function private.matching_item(slot, partial)
+	local item_info = Aux.info.container_item(unpack(slot))
+	return item_info and item_info.item_key == state.item_key and Aux.info.auctionable(item_info.tooltip) and (not partial or item_info.count < item_info.max_stack)
+end
+
+function private.find_empty_slot()
+	for slot, type in Aux.util.inventory() do
+		if type == 1 and not GetContainerItemInfo(unpack(slot)) then
+			return slot
+		end
+	end
+end
+
+function private.find_charge_item_slot()
+	for slot in private.item_slots(state.item_key) do
+		if private.charges(slot) == state.target_size then
 			return slot
 		end
 	end
 end
 
 function private.move_item(from_slot, to_slot, amount, k)
-	local size_before = private.stack_size(to_slot)
-		
+
+	if private.locked(from_slot) or private.locked(to_slot) then
+		return Aux.control.wait(k)
+	end
+
 	amount = min(private.max_stack(from_slot) - private.stack_size(to_slot), private.stack_size(from_slot), amount)
+	local expected_size = private.stack_size(to_slot) + amount
 
 	ClearCursor()
-	SplitContainerItem(from_slot.bag, from_slot.bag_slot, amount)
-	PickupContainerItem(to_slot.bag, to_slot.bag_slot)
-	
-	return Aux.control.wait_until(function() return private.stack_size(to_slot) == size_before + amount end, k)
-end
+	SplitContainerItem(from_slot[1], from_slot[2], amount)
+	PickupContainerItem(unpack(to_slot))
 
-function private.item_key(slot)
-	local container_item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
-	return container_item_info and container_item_info.item_key
-end
-
-function private.stack_size(slot)
-    local container_item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
-    return container_item_info and container_item_info.count or 0
-end
-
-function private.item_charges(slot)
-    local container_item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
-	return container_item_info and container_item_info.charges
+	return Aux.control.wait_until(function() return private.stack_size(to_slot) == expected_size end, k)
 end
 
 function private.process()
 
+	if not state.target_slot or not private.matching_item(state.target_slot) then
+		state.target_slot = private.find_item_slot()
+		if not state.target_slot then
+			return public.stop()
+		end
+	end
+
+	if private.charges(state.target_slot) then
+		state.target_slot = private.find_charge_item_slot()
+		return public.stop()
+	end
+
 	if private.stack_size(state.target_slot) > state.target_size then
-		local empty_slot = private.find_empty_slot()
-		
-		if empty_slot then
+		local slot = private.find_item_slot(true) or private.find_empty_slot()
+		if slot then
 			return private.move_item(
 				state.target_slot,
-				empty_slot,
+				slot,
 				private.stack_size(state.target_slot) - state.target_size,
-				function()
-					return private.process()
-			end)
-		else
-			local next_slot = state.other_slots()
-			if next_slot then
-				return private.move_item(
-					state.target_slot,
-					next_slot,
-					private.stack_size(state.target_slot) - state.target_size,
-					function()
-						return private.process()
-				end)
-			end
+				private.process
+			)
 		end
 	elseif private.stack_size(state.target_slot) < state.target_size then
-		local next_slot = state.other_slots()
-		if next_slot then
+		local slot = private.find_item_slot()
+		if slot then
 			return private.move_item(
-				next_slot,
+				slot,
 				state.target_slot,
 				state.target_size - private.stack_size(state.target_slot),
-				function()
-					return private.process()
-				end
+				private.process
 			)
 		end
 	end
@@ -99,16 +107,14 @@ function private.process()
 	return public.stop()
 end
 
-function private.max_stack(slot)
-    local container_item_info = Aux.info.container_item(slot.bag, slot.bag_slot)
-    return container_item_info and container_item_info.max_stack
-end
-
 function public.stop()
 	if state then
 		Aux.control.kill_thread(state.thread_id)
 
 		local callback, slot = state.callback, state.target_slot
+		if not private.matching_item(slot) then
+			slot = nil
+		end
 		
 		state = nil
 		
@@ -121,23 +127,12 @@ end
 function public.start(item_key, size, callback)
 	public.stop()
 
-	local slots = private.item_slots(item_key)
-	local target_slot = slots()
-
 	local thread_id = Aux.control.new_thread(private.process)
 
 	state = {
 		thread_id = thread_id,
+		item_key = item_key,
 		target_size = size,
-		target_slot = target_slot,
-		other_slots = slots,
 		callback = callback,
 	}
-
-	if not target_slot then
-		public.stop()
-	elseif private.item_charges(target_slot) then
-		state.target_slot = private.find_charges_item_slot(item_key, size)
-		public.stop()
-	end
 end
\ No newline at end of file
diff --git a/tooltip.lua b/tooltip.lua
index 1b0e720..5ba4387 100644
--- a/tooltip.lua
+++ b/tooltip.lua
@@ -239,15 +239,11 @@ end
 function game_tooltip_hooks:SetAuctionSellItem()
     local name, _, quantity, _, _, _ = GetAuctionSellItemInfo()
     if name then
-        for bag = 0, 4 do
-            if GetBagName(bag) then
-                for slot = 1, GetContainerNumSlots(bag) do
-                    local link = GetContainerItemLink(bag, slot)
-                    if link and ({Aux.info.parse_hyperlink(link)})[5] == name then
-                        private.extend_tooltip(GameTooltip, link, quantity)
-                        return
-                    end
-                end
+        for slot in Aux.util.inventory() do
+            local link = GetContainerItemLink(unpack(slot))
+            if link and ({Aux.info.parse_hyperlink(link)})[5] == name then
+                private.extend_tooltip(GameTooltip, link, quantity)
+                return
             end
         end
     end
diff --git a/util.lua b/util.lua
index 548fafa..c1f34b3 100644
--- a/util.lua
+++ b/util.lua
@@ -9,11 +9,16 @@ function public.id(object)
 end
 
 function public.table_eq(t1, t2)
+	if not t1 or not t2 then
+		return false
+	end
+
 	for key, value in t1 do
 		if t2[key] ~= value then
 			return false
 		end
 	end
+
 	return true
 end
 
@@ -46,32 +51,38 @@ function public.trim(string)
 	return string
 end
 
-function Aux.util.inventory_iterator()
-    local inventory = {}
-    for bag = 0, 4 do
-        if GetBagName(bag) then
-            for bag_slot = 1, GetContainerNumSlots(bag) do
-                tinsert(inventory, { bag = bag, bag_slot = bag_slot })
-            end
-        end
-    end
+function public.inventory()
+	local bag, slot = 0, 0
 
-    local i = 0
-    local n = getn(inventory)
-    return function()
-        i = i + 1
-        if i <= n then
-            return inventory[i]
-        end
-    end
+	return function()
+		if not GetBagName(bag) or slot >= GetContainerNumSlots(bag) then
+			repeat
+				bag = bag + 1
+			until GetBagName(bag) or bag > 4
+			slot = 1
+		else
+			slot = slot + 1
+		end
+
+		if bag <= 4 then
+			return { bag, slot }, public.bag_type(bag)
+		end
+	end
 end
 
-function public.loop_inventory(f)
-	for bag = 0, 4 do
-		if GetBagName(bag) then
-			for slot = 1, GetContainerNumSlots(bag) do
-				f(bag, slot)
-			end
+do
+	local bag_types = { GetAuctionItemSubClasses(3) }
+
+	function public.bag_type(bag)
+		if bag == 0 then
+			return 1
+		end
+
+		local link = GetInventoryItemLink('player', ContainerIDToInventoryID(bag))
+		if link then
+			local item_id = Aux.info.parse_hyperlink(GetInventoryItemLink('player', ContainerIDToInventoryID(bag)))
+			local item_info = Aux.info.item(item_id)
+			return Aux.item_subclass_index(3, item_info.subclass)
 		end
 	end
 end