I'm not a haggler, but as a buyer, it can be off putting to me when a seller mentions things like "no offers", "price is firm", or "as-is no returns". It just gives off the impression that the seller is a very stern person and may be hard to deal with if there is a problem.
As a seller, I completely get it. I've listed stuff for sale various other places and been bombarded with offers that I wasn't interested in and got tired of fielding questions from tire kickers that had no interest in purchasing at the price I wanted, so I began putting those statements into my own ads in those places. It weeded out most of the hagglers, but also probably turned off a lot of people that would've otherwise been interested at the asking price.
From my personal experiences, the hagglers have generally been the most nit picky buyers once they receive an item....looking for that partial refund I guess. I list all my stuff BIN with no best offer here, but I still get people messaging me with offers. If it's well below what I would be willing to go, I just ignore them. If their offer is borderline, I'll counter-offer. If it's something I just listed, but still may consider selling for what a person offers, I will respond and tell them I'd rather wait a few days to see if I can get the asking price, but if they still see it listed a few days later, send me another message. If it's something that I have no intention of selling for less than the asking price, I'll generally just ignore most offers and only reply to the ones that are looking for small discounts. The ones that claim they can get it cheaper elsewhere, I will gladly send them a link to a cheaper priced item (if there is one) that they can go buy. I'm not selling to make a living, just getting rid of stuff I don't want anymore, so my ultimate goal isn't to make sales, my goal is to sell my stuff to people that I'm fairly confident won't end up being a nightmare to deal with.
