Hello, Interested in the bike?
Hello. I'm interested in the bike. How old is it?
It's 4 years old, but it is in great shape. tires look practically brand new.
How good is the TREK brand? I never heard of it
Trek is very well respected in the biking community. This is a great bike to commute to work with, or to get into road-biking  
Great. Would you accept $157 for the bike?
I think that's a bit low for a bike in this condition, I could go as low as $200, but I could deliver it too you
I can't do $200. Would you accept $180 and I pick it up from you?