Hey there.
Hello how are you?
Good and yourself?
Fine thanks.
Great! I'm looking to buy your dictionary dataplus. I think $75 is more than I'm willing to pay. 
It is in excellent working condition.
It is a used item though and is missing the manual. Would you be prepared to go down to $50?
I don't think I could go quite that low. I think $60 is probably the lowest I could go.
What about $57?
Ok I could do $57.