Hmmm, I am thinking that NCL's drink prices are pretty standard fleet wide. Count on paying around $4 for a cocktail. However they always have a daily drink special for less and they are always popular.
Wine is expensive and the glasses are small. I prefer to take my own wine and simply pay the corkage fee ($10) While you can bring wine on board they will not allow you to take liquor....hence the old bourbon in the coke bottle trick..VBG.