Hi, I'm interested in the phone, how much are you asking?
Hi, do you need your phone unlocked?
Yes, how much will it cost?
$50 to unlock you phone.  deal?
That is a little outside of my budget, could you do it for $42.50?
I will throw in a free headset if you can pay $47.  Deal?
How about the headset and I can wait a day or two to pick it up, so you can get to other customers, for $44.  Deal?
Okay, deal!