His: 2002 Trek Fuel 80.  Frame size: 17.5"(I think...the frame doesn't say, but the original receipt says 17.5).  Full suspension.  This bike has had moderate use, but has been well maintained.  New chain and cassette. 

 

Hers: 2009 Trek 4500 16"  hardtail.  This bike has been ridden once, maybe twice since she has owned it, and that was very light use.  It is like new.

 

$300 each, or both for $500.