I used www.cruisecompete.com to get better prices on a Hawaii cruise for late September. The NCL price for balcony was $999pp plus tax. (approx $1060pp all in). The bids came in between $880 and $950 all in. Nice thing is there is no obligation to buy anything. Various cruise agencies will bid for your business.

Note: I just used the service and it saved some $ for me. Not afflilated with them in any way. Just a consumer that used their service.