Hi.  Can you unlock my apple phone?
Yes, I sure can. My price is $50 a phone, including apples.
Would you accept $25?  I think this is the average price for phone unlocking. 
If it were the average price, I'd be out of business, I cant really negotiate.
Hi.  can you unlock my iphone? 
I sure can. My price is $50 a phone.
$25 is my budget for this, but what are the perks for $50? 
I really cant do much for $25, But if you'd like, I can include a new case for it as well.
That would be perfect.  I need a new case. 
Good deal.