Hi, I have an iPhone for $200.  Are you interested?  It's unlocked.
Yes, i am interested but the price is a bit high for me. I will offer 120 for it. Are there any problems with it?
No problems with the phone.  It works great.  I can give you a free headset too for the price of $200.  deal?
I can't do 200. But, I can do 140
The phone is worth a lot more than that.  I can come down to $190 if you can pick it up today.  I'll still give you the headset.  deal?
Okay, well how about we meet halfway. 170?
If you can come up to $177, we have a deal.  
okay, that works for me. deal