NPC Sucky but working House Seller.

local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
NpcSystem.parseParameters(npcHandler)
local talkState = {}
local house = {}
local hasHouse = {}
local eachTilePrice = 200 -- price for each house tile
local maxHouses = 100 -- how many houses does your server have
	
function onCreatureAppear(cid)				npcHandler:onCreatureAppear(cid)			end
function onCreatureDisappear(cid)			npcHandler:onCreatureDisappear(cid)			end
function onCreatureSay(cid, type, msg)			npcHandler:onCreatureSay(cid, type, msg)		end
function onThink()					npcHandler:onThink()					end

function creatureSayCallback(cid, type, msg)
	if(not npcHandler:isFocused(cid)) then
		return false
	end

	local talkUser = NPCHANDLER_CONVBEHAVIOR == CONVERSATION_DEFAULT and 0 or cid
	
	if msgcontains(msg, "free") or msgcontains(msg, "offer") then
		local freeHouses = ""
		local z = ""
		for i = 1, maxHouses do
			if getHouseOwner(i) == 0 then
				if freeHouses == "" then z = "" else z = "," end
				freeHouses = freeHouses..""..z.." "..i
			end
		end
		selfSay("You can buy the following houses: "..freeHouses..".", cid)
	elseif msgcontains(msg, "house") then
		for i = 1, maxHouses do
			if getHouseOwner(i) == getPlayerGUID(cid) then
				hasHouse[cid] = 1
			end
		end
		if hasHouse[cid] == 1 then
			selfSay("You already own a house!", cid)
		else
			selfSay("Which house would you like to buy?", cid)
			talkState[cid] = 1
		end
	elseif msgcontains(msg, "yes") and talkState[cid] == 2 then
		if doPlayerRemoveMoney(cid, getHouseTilesSize(house[cid]) * eachTilePrice) == TRUE then
			selfSay("Congratulations, the house #"..house[cid].." is yours!", cid)
			setHouseOwner(house[cid], getPlayerGUID(cid))
			talkState[cid] = 0
		else
			selfSay("Ehh... Not enough gold. You need "..getHouseTilesSize(house[cid]) * eachTilePrice.." gold pieces to buy it.", cid)
			talkState[cid] = 0
		end
	elseif msgcontains(msg, "no") and talkState[cid] == 2 then
		selfSay("As you wish...", cid)
		talkState[cid] = 0
	elseif talkState[cid] == 1 then
		if isNumber(msg) == TRUE then
			if tonumber(msg) < #houses then
				if getHouseOwner(msg) == 0 then
					selfSay("Uhm... Would you like to buy house #"..msg.." for "..getHouseTilesSize(msg) * eachTilePrice.." gold coins?", cid)
					talkState[cid] = 2
					house[cid] = msg
				else
					selfSay("Sorry, this house is already owned by someone.", cid)
					talkState[cid] = 0
				end
			else
				selfSay("Sorry, there is not that much houses, we have "..maxHouses.." houses", cid)
			end
		else
			selfSay("I could not understand, please repeat the house number.", cid)
			talkState[cid] = 1
		end
	end
	return TRUE
end
		
npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)
npcHandler:addModule(FocusModule:new())