I think someone making a low ball is chancing their arm and there's no need to be offended. Be polite, if you must reply, or just ignore, the offer has term limits here. I usually reply (must be my Catholic upbringing) in the hope that with polite conversations, both parties might come to a meaningful understanding.
Am more frustrated by people asking unreasonable prices for used gear -- those who think they can own something for years and then have it fetch 80% of its current MSRP. Right now, there's a few deals on discontinued model amps from a well known manufacturer, and those selling used versions still reference the original MSRP as the basis for their near equivalent prices. Sorry, an item gets discontinued and discounted, the old MSRP is no longer relevant. I don't even being to negotiate with those folks. At the end of the day, it's best not to get emotionally invested in folks' asking prices or offers. The market does not really lie.
Am more frustrated by people asking unreasonable prices for used gear -- those who think they can own something for years and then have it fetch 80% of its current MSRP. Right now, there's a few deals on discontinued model amps from a well known manufacturer, and those selling used versions still reference the original MSRP as the basis for their near equivalent prices. Sorry, an item gets discontinued and discounted, the old MSRP is no longer relevant. I don't even being to negotiate with those folks. At the end of the day, it's best not to get emotionally invested in folks' asking prices or offers. The market does not really lie.