What's the tractor worth in it's shape.. use it as a bargining tool. If it's worth 1000 in your eyes (not sure what you think the sign is worth) could say i'll buy it for 1500 if you throw in the sign.. Everything up here is spendy.. More money then brains for a lot of people up here in the land of oil.. :wallbanging:
Ask them to put a crazy number on it. Once they put a number on it you are halfway there and you can start negotiating. Also like TG was talking about bundle some signs inside with the one outside and see what they will do.