EDIT:
--Written by RoShambo
--Remove credits and you will die!
--Sample plugin for you, for the commands !build tower and !build turret
--VB style language, very easy to learn!
function printf(...) 
   io.write(string.format(unpack(arg))) 
end
function InputConsole(...)
   Console_Input(string.format(unpack(arg)))
end

function OnChat(pID, Type, Message)
   if Message == "!buy arty" then
      if Purchase_Item(Get_GameObj(pID), 450) == 1 then
         local pos = Get_Position(Get_GameObj(pID))
         pos:AssignZ(pos:GetZ()+5)
         pos:AssignX(pos:GetX()+5)
         Create_Object("Nod_Mobile_Artillery_Player", pos)
      else
         InputConsole("ppage %d You don't have enough money", pID)
      end
   end

   if Message == "!fly" then
      Toggle_Fly_Mode(Get_GameObj(pID))
   end
   if Message == "!build turret" then
	local pos = Get_Position(Get_GameObj(pID))
		if Get_Team(pID) == 0 then
			if Get_Money(pID) < 600 then
				InputConsole("ppage %d You need 600 credits", pID)
			else
				turret = Create_Object("Nod_Turret_MP_Improved", pos)
				if turret == nil then
					InputConsole("ppage %d Error creating turret", pID)
				else
					Disable_Physical_Collisions(turret)
					Set_Money(pID, Get_Money(pID)-600)
				end
			end
		else
			InputConsole("ppage %d You need to be on Nod", pID)
		end
	end
	if Message == "!build tower" then
		local pos = Get_Position(Get_GameObj(pID))
		if Get_Team(pID) == 1 then
			if Get_Money(pID) < 600 then
				InputConsole("ppage %d You need 600 credits", pID)
			else
				pos:SetZ(pos:GetZ()+8)
				turret = Create_Object("GDI_Guard_Tower", pos)
				if turret == nil then
					InputConsole("ppage %d Error creating tower", pID)
				else
					Disable_Physical_Collisions(turret)
					Set_Money(pID, Get_Money(pID)-600)
				end
			end
		else
			InputConsole("ppage %d You need to be on GDI", pID)
		end
	end

end


end

function OnPlayerJoin(pID, Nick)

end

function OnPlayerLeave(pID)

end

function OnHostMessage(ID, Type, Message)

end

function OnLevelLoaded()
   
end

function OnLevelEnded()

end

function OnConsoleOutput(Message)

end

function OnDDERecived(Message)

end

function OnObjectCreate(Object)

end