I had heard about the different Flea Markets in the city but never ventured to one, as much as I have been in that area. We stumbled upon the Hells Kitchen Flea Market (link) on West 39th street between 9th and 10th avenue a couple blocks from Port Authority and very close to Time Square.
Beware, there is an unusual amount of pictures. Take a gander.
things from different parts of Africa.
you may also find this guy who was playing music with a large radio attached to a dolly/cart...
beware, magazines with lots of legs
...there is some house ware and random jewelery
...cool street signs and license plates, if that's your thing
If you are in the city on a saturday or sunday morning until 5pm , I highly recommend this little street show fro all your discovering needs.