Dry Ice in or around Chelsea?
Dry Ice - you can get a small piece for about $6 at the Ice place on 48th near the corner of 9th Avenue. It's on the same block as grays papaya and around the corner from Mangario Brothers (in case I have the street wrong)
many places make you buy a bigger piece.
warning. dry ice doesn't last long so buy it on the same day you want to use it otherwise it will just evaporate.