You can save a little money by waiting until the last minute to book the Sky. The new per diem cost for two people is $259 a day, down from a high of $293/day in June. One of the itineraries has sold out in the cheapest inside category, but balcony cabins are still available.
It now costs about $293 a day for two people to sail on the Norwegian Sky in January 2017. The per diem cost has gone up $8 a day due to an increase in taxes, port fees, and gratuities. The base price of the cruises has not changed since my first post in February.