When negotiating price for anything, i play it hard.
Most folks want to negotiate, and most aren't real good at it.
They have a dollar figure in their mind as to what their item is worth, and i, as the buyer, have to fetter it out through creative discussion.
So, i ask questions. Lots of them. And, i watch their eyes. Unless they're a pathological liar, and can lie without flinching in the slightest with their eyes or voice, they will give me the information i want to guide my price offers.
If someone is asking 5k for a horse for example, their ducks had best be in line marching like little soldiers. I will look for any holes to poke in their story, find the missing information, and generally ask the questions i already know the answers to because they gave them to me.
I have purchased $4500 cars for less than half of the asking price.
Some folks think their stuff is solid gold. They never see my money.
Some folks know realistically what their stuff is worth, and sell accordingly. They did their research, they know the markets, and they know what comparable items are being sold for.
Others have no idea what they have in hand, so they highball the price hoping for an idiot.
I prefer to deal with the last two, as thats where the best deals are made for both parties.
Two points to ensure you NEVER do- call someone out as a liar on the value of their stuff, and never offer full price.
If i am intending to lowball them, i will preface it by leading into it with a question.
I will ask, "i know you're asking x for your widget, but the market is really soft. I like your widget, but from what i've seen, and please understand i don't intend to sound disrespectful, but x-40% is about what i'm thinking. What are your thoughts?"
This leads into negotiations, and you've softened it so they'll continue to negotiate with you.
Yes, it runs the risk of ticking them off, but most folks interested in selling, especially in this economy, want to negotiate to get their item sold.
It's a feel thing, and what i sense when talking with them.
How attached are they to the item?
Are they in distress financially, compelling the sale?
Where is their motivation to sell the item coming from?
How pressed are they to sell it?
Be their friend, help them out, and you'll get the best deal possible.