Hi There!  I would like to buy the phone, but I only have $300.  I do have some other electronics that I could trade with the cash to sweeten the deal.  Are you interested?
No, I can't take any trades.  
Are you willing to come down on the price at all?  What is you best price?
My best price is firm at $650.  The product is brand new, still in the box, and is the most popular variant.
I understand.  I think I can borrow some money.  Can I pay $400?
No, the price is $650.
Is anybody else trying to buy this phone?  You have a potential buyer, but you won't negotiate a fair price.  I can go to the store and pay $650.  I'm looking for a deal.  $500 is my final offer.  That is a fair price.
You won't find it in the store, not this color.
The color is a minor detail.  I always keep expensive phones in a case.  You can buy any color case, so the color isn't going to make me pay $150 more than a fair price.  $500 Deal?
No deal.