They're here, they have always been here and they will always be here. For me, if the offer is way too low, nowadays I just go "Ha! The nerves!" and ignore it. I used to reply to those but some of them got insulted by my polite (or so I thought) replies. However, sometimes the offer is for some junk that I want to rid off but haven't got around to reducing the price, then I go "Ha ha! The luck!". If the offer is too low, but within what I think is negotiable, then I negotiate, most times this works out well.