What to do with very low offer on an item for sale

I price my things rather fairly to ensure a quick sale so I don’t have much room for haggling. Low balls I ignore, I simply say, thank you for the offer but I’m going to pass. I don’t counter-offer at all. 
 

I recently made an offer on eBay for an item that was $500. I offered $475 and the guy went ballistic on me. This item had been re-listed twice already. I ended up buying the same item for less from another seller. People are just weird. 

I'm happy to communicate with anybody who responds to a listing, even if they just have an informational question and are not necessarily even looking to buy. If somebody makes a low-ball offer, I just say, "Sorry, that won't do it; good luck!" - I don't get bent out of shape about it. 

@faustuss - the DOG! 

Many thanks to all who responded.

I had no idea it would create such responses!  I think that if (when) I offer more of my unneeded stuff I shall know how to manage ridiculous offers.  How would a car salesman respond if I offered $20k on an $80k car?

I am grateful to be part of this community with the common goal of greater enjoyment of recorded music.  Being retired, and not close to many others who scare about their listening, it means a lot.

I would always thank them for making an offer but you are declining it.  No reason to be insulted.  I have set up (3) systems buying used.  I tend to "lowball" - but never 25% of asking.  Sometimes the seller and I reach a deal right away.  Other times they decline then approach me in 30 or 60 days if the unit hasn't sold.  Usually I have bought a different piece by then and have had to decline.  And sometimes they get pissy with me.  There are multiple reasons to low ball.  The most common for me is I am ready to buy let's say a speaker for $ Xk but I see a Wilson Benesch that looks good too. That guy wants $ X+Yk for the WB.  I may throw him an offer for $ X to see if he wants to sell it.  Sometimes they make the decision difficult and other times not so much.  Another reason someone alluded to is budget constraints.  Another is just the risk associated with buying a piece sight unseen and/or unheard.  I dont live in a major metro area so i cannot always audition the speaker and need to be able to get my money out of it if i dont like it.  The key is to take the high road.   You can also use the word Firm in your ad.  Good luck !

"How would a car salesman respond if I offered $20k on an $80k car?” - good question! lemons sold to squeeze a juice from buyers! LOL 

my answer is “depends”! -is the car a brand new one, no previous owners/mileage driven? -is the car of well established brand, reliable model, with predictable life-time, 200k+ /mileage before “problems” start? -assuming it’s second/third hand one, what is the rest of life/milage estimate, for buyer?