local money = 500

function onSay(cid, words, param)

local tab = {
    ["helmet"] = {id = 2457, toid = 2491},
    ["boots"] = {id = 2643, toid = 2645},
}

    if tab[param] then
      if doPlayerRemoveMoney(cid, money) then
         if doPlayerRemoveItem(cid, tab[param].id, 1) then
            doPlayerAddItem(cid, tab[param].toid, 1)
                 else
            doPlayerSendCancel(cid, "You don't change this item.")
         end
            else
         doPlayerSendCancel(cid, "You don't have money.")
      end
    end

    return true
end