Hello, I saw your advertisement for a lamp and I would like to offer you $40 for it.
Hello.  Glad you are interested in the lamp. It is a great piece and vintage.  I could accept $75.
Well, it's listed at $70 and I'm interested in the design, but I would have to do a conversion to the regular bulb.
Yes, I will accept $70 for the piece.  You will be pleased with the look and the great condition.
I think that's an acceptable price, but as I mentioned I'll have to do the conversion.  The best I could offer is $50.
How about I meet you at $55?
Sure, I think that's reasonable.  Thanks.
Great!