It depends on if his price was good or not. If the price was already attractive, or the going rate, then a -20% offer is too low. If he was high on his price, then it is in line. If you are buying this type of item, you know what the going rate should be. If you were trying to get 20% below that, then you should expect a response like that. Low ballers are not viewed very well on this site.
