Raleigh Twenty in Stamford, CT for $185:
http://newyork.craigslist.org/fct/bik/754253356.html

A-Bike in Bay Ridge, NYC for $100:
http://newyork.craigslist.org/brk/bik/754483557.html

Puma Biomega in Manhattan for $700:
http://newyork.craigslist.org/mnh/bik/753903419.html

Raleigh RSW MKII in Manhattan for $200 (it doesn't fold, but is small wheeled):
http://newyork.craigslist.org/mnh/bik/753230641.html

Bike Friday Crusoe in upper Manhattan for $700:
http://newyork.craigslist.org/mnh/bik/753200457.html