I couldn't decide whether to put this on the Tourist Trap page or not. I guess not. It's not a bad deal if you get one of the packages with the Metrocard as well. It's also a cute idea, and none of the people getting on or off seemed disgruntled or unhappy. It stops at South Street Seaport, Batter PArk, North Cove, Pier 62, and Pier 84. So, it's convenient for the Intrepid Museum, Chelsea Piers, and Statue of Liberty visiting.
A single stop (commuter style) is $4; an all day pass is $15; a fun pass (all day plus a metrocard) is $19. Children and seniors are a few dollars less. Children under 2 are free of charge.