I sometimes use the hand car wash place in Chelsea (24th/10th) run by an Asian guy next to Highline (the guy can make millions by building condos and closing the car wash). It would run you around $25-$30. If you decide go there, make sure only the tall African guy washes the car as he is really good about the paint, using buckets, etc. There is another one on Westside highway but they charge $49 for hand car wash.
Sometimes, I drive to Jersey and get a hand wash there but unfortunately they can be swirl factories (you drive in, army of illegalís working who donít really care about paint, etc). Unfortunately, my car got swirls.
Ideally, if I can find a place to do car wash myself in Manhattan with 2 buckets, etc, I would do that. I live in a doorman building and I may ask the building janitor if I can use the water from the building and wash the car on street.