Here's one I recently grabbed from CL for $160 for my wife. It's a light, steel framed '05 Jamis Coda Sport. I did have to tune it up, so even a $100 - $150 most likely will end up around $200 or more to get it working right.

I upgraded the handlebars, grips, stem extender, pedals, and tires for her, but the wheel needed truing and all the cables, housing, and brake pads needed replacing. You won't need to do all thing things I did, but you should consider the cost of getting a decent tune-up.

But, now she has a kick ass "new" bike.