Os items para receber o addon é configurável.

talkactions.XML

<talkaction words="!rank" separator=" " script="buyaddon.lua"/>

buyaddon.lua

local text = '--Addon List--\n!buyaddon "citizen\n!buyaddon "hunter\n!buyaddon "mage\n!buyaddon "knight\n!buyaddon "summoner\n!buyaddon "warrior\n!buyaddon "barbarian\n!buyaddon "druid\n!buyaddon "wizard\n!buyaddon "oriental\n!buyaddon "pirate\n!buyaddon "assassin\n!buyaddon "beggar\n!buyaddon "beggar\n!buyaddon "shaman\n!buyaddon "norseman\n!buyaddon "nightmare\n!buyaddon "jester\n!buyaddon "brotherhood\n!buyaddon "warmaster\n--Addon List End--'

function onSay(cid, words, param)
local player = Player(cid)
    local cfg = {
        ["citizen"] = {
            outfit = {
                male = 128,
                female = 136,
                addon = 3,
                storage = 10031
            },
            items = {
                {5878,100}
            }
        },
        ["hunter"] = {
            outfit = {
                male = 129,
                female = 137,
                addon = 3,
                storage = 10032
            },
            items = {
                {5876, 100},{5948, 100}
            }
        },
        ["mage"] = {
            outfit = {
                male = 130,
                female = 138,
                addon = 3,
                storage = 10033
            },
            items = {
                {2160,10}
            }
        },
        ["knight"] = {
            outfit = {
                male = 131,
                female = 139,
                addon = 3,
                storage = 10034
            },
            items = {
                {5880,100},{5893, 100}
            }
        },
        ["summoner"] = {
            outfit = {
                male = 133,
                female = 141,
                addon = 3,
                storage = 10035
            },
            items = {
                {2160,10}
            }
        },
        ["warrior"] = {
            outfit = {
                male = 134,
                female = 142,
                addon = 3,
                storage = 10036
            },
            items = {
                {5925, 100},{5899, 100},{5919, 1},{5880, 100}
            }
        },
        ["barbarian"] = {
            outfit = {
                male = 147,
                female = 143,
                addon = 3,
                storage = 10037
            },
            items = {
                {5911, 50},{5910, 50},{5879, 100}
            }
        },
        ["druid"] = {
            outfit = {
                male = 148,
                female = 144,
                addon = 3,
                storage = 10038
            },
            items = {
                {5896, 50},{5897, 50}
            }
        },
        ["wizard"] = {
            outfit = {
                male = 149,
                female = 145,
                addon = 3,
                storage = 10039
            },
            items = {
                {2536, 1},{2492, 1},{2488, 1},{2123, 1},{5922, 50}
            }
        },
        ["oriental"] = {
            outfit = {
                male = 150,
                female = 146,
                addon = 3,
                storage = 10040
            },
            items = {
                {5883, 100},{5895, 100},{5912, 100}
            }
        },
        ["pirate"] = {
            outfit = {
                male = 151,
                female = 155,
                addon = 3,
                storage = 10041
            },
            items = {
                {6098, 100},{6126, 100},{6097, 100}
            }
        },
        ["assassin"] = {
            outfit = {
                male = 152,
                female = 156,
                addon = 3,
                storage = 10042
            },
            items = {
                {5898, 30},{5882, 10},{5881, 30},{5895, 20},{5905, 10}
            }
        },
        ["beggar"] = {
            outfit = {
                male = 153,
                female = 157,
                addon = 3,
                storage = 10043
            },
            items = {
                {5878, 50},{2743, 30},{5913, 20},{5894, 10}
            }
        },
        ["shaman"] = {
            outfit = {
                male = 154,
                female = 158,
                addon = 3,
                storage = 10044
            },
            items = {
                {3955,5},{5810, 5},{3966, 5},{3967, 5}
            }
        },
        ["norseman"] = {
            outfit = {
                male = 251,
                female = 252,
                addon = 3,
                storage = 10045
            },
            items = {
                {7290,15}
            }
        },
        ["nightmare"] = {
            outfit = {
                male = 268,
                female = 269,
                addon = 3,
                storage = 10046
            },
            items = {
                {6500,200}
            }
        },
        ["jester"] = {
            outfit = {
                male = 273,
                female = 270,
                addon = 3,
                storage = 10047
            },
            items = {
                {2160, 25}
            }
        },
        ["brotherhood"] = {
            outfit = {
                male = 278,
                female = 279,
                addon = 3,
                storage = 10048
            },
            items = {
                {6500,200}
            }
        }
    }
    local v, removeItems = cfg[param], 0, 0
          if(param == "") then
              player:sendTextMessage(MESSAGE_INFO_DESCR, 'Please type !addon "outfit')
        player:showTextDialog( 5914, text)
    return false
    end
    if (v == nil) then
          player:sendTextMessage(MESSAGE_INFO_DESCR, "There is no such as outfit named "..param..", here is the list of available outfit.")
        player:showTextDialog(5914, text)
    return false
    end
    if(player:getStorageValue(v.outfit.storage) < 1) then
        for i = 1, #v.items do
            if(player:getItemCount(v.items[i][1]) >= v.items[i][2]) then
                removeItems = removeItems+1
            end
        end
        if(removeItems == #v.items) then
            if(player:getSex(cid) == 1) then
                player:addOutfitAddon(v.outfit.male, v.outfit.addon)
            elseif(player:getSex(cid) == 0) then
                player:addOutfitAddon( v.outfit.female, v.outfit.addon)
            end
            for i = 1, #v.items do
                player:removeItem( v.items[i][1], v.items[i][2])
            end
              player:sendTextMessage(MESSAGE_INFO_DESCR, "Enjoy your new addons to your "..param.." outfit!")
                    player:getPosition():sendMagicEffect(CONST_ME_FIREWORK_YELLOW)
            player:setStorageValue( v.outfit.storage, 1)
        else
            for i = 1, #v.items do
                  player:sendTextMessage(MESSAGE_INFO_DESCR, "Tu necesitas " .. v.items[i][2] .. "x " .. ItemType(v.items[i][1]):getName() .. " para obtener el "..param.." addon.")
            end
        end
    else
          player:sendTextMessage(MESSAGE_INFO_DESCR, "Usted ya obtuvo el "..param..".")
    end
    return false
end

Créditos : david.

[19/08/2016 15:36:26] [Error - TalkAction Interface] 
[19/08/2016 15:36:26] data/talkactions/scripts/buyaddon.lua:onSay
[19/08/2016 15:36:26] Description: 
[19/08/2016 15:36:26] data/talkactions/scripts/buyaddon.lua:4: attempt to call global 'Player' (a nil value)
[19/08/2016 15:36:26] stack traceback:
[19/08/2016 15:36:26]     data/talkactions/scripts/buyaddon.lua:4: in function <data/talkactions/scripts/buyaddon.lua:3>