What is a lowball offer? How low is low?


Recently I was looking at 2 -3 preamps. One was particularly interesting which was a Conrad Johnson 16LS2. The asking price was $3500. I have always wanted the 16LS2. But it was out of my price range. I couldn't make a serious offer. So I didn't and moved on. A few days later I see that it has sold for $2500! What? That was in my budget. But I would have considered that more an insult than a offer. And because I didn't want to insult the seller, I lost a good preamp to someone who was willing to take the chance. So what is the lesson learned here? Apparently I should insult more sellers . The seller wasn't insulted after all. he sold it for $2500. Or is the lesson that I take this stuff too seriously?Should sellers be insulted when offered 50% of their price?  I had thought that 10-15% below the asking price was a realistic offer. Now I'm not sure. So what do you consider a low ball offer? And please, I understand that a product is worth what someone is willing to pay. So no economic lessons please
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Another situation is where a replacement model is more expensive... example... item A is $100 new and the “updated version” has jumped to $125....item A may now sell for 60-70% used because the replacement is more expensive. 


One one final thought that sometimes I think is ignored... it’s not what you pay, but what you can resell it for in a couple years when it’s time... examples... you know that KEF, Audio Research, parasound and others hold their value pretty well over time... so if you can resell for 50% then who cares if you have to pay 60%... your real cost was only 10%!!!
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It's all kidology and as already stated it might be as much as HOW you approach making your lower offer that wins the day.

I never get mad or insulted at low offers and usually just counter with what figure I really want to get.
About 50% of the time it gets sold that way. If not, well still plenty of fish in the ocean.

Point being, do not be afraid to offer what you believe it is worth to you and you alone but do be prepared to back it up with a solid purchase if accepted.
Good responses and helpful to someone like me who really doesn't care to do the proverbial dance (dickering) without looking the seller in the eye. Quite honestly, it took me a long time to become comfortable with the process of "bargaining".I learned the art of it when I rode 450 miles to buy a car. They knew I was serious and so tried to get more than top dollar. It took a few hours but I got it for $300 more than I had set out to pay. that was on a $20K car. So I felt good about it.
Anyway, thanks for the feedback. 
You're not going to be incarcerated, flogged, or executed. Just tell the seller what you can afford and ask them if they would kindly consider your offer. A little respect is the key. IMO