How are the tires on this?
The tires are great.  My wife only used this bike for 3 months before she switched to a hybrid.  The whole bike is in fabulous condition.
Oh wow. So there are no problems with it at all?
None.  I am only selling it because we have enough bikes around our place and need some space.
That makes sense well I have $50 cash on me and a giftcard for $10 to the mall I'd like to offer you
I'm not a mall guy at all, and $50 is pretty cheap for such an amazing ride.  I'm willing to go $75.  How does that sound to you?
If you can throw in a helmet you've got a deal. 
I can do that!  You know women--my wife bought a brand new helmet to go with her new bike, so we have a practically new one we can throw in no problem.  You've got yourself a deal.