Hi cold in ct, welcome to Cruise-Chat. The price depends on the liquor used. If you use bar alcohol, the drinks are less expensive than if you use call liquor. The best thing for wine with dinner is to purchase a bottle, then they will cork it for you and serve it again until the bottle is gone. It's less expensive that way. The price for a glass of wine is around $6/glass, a martini will range from $6-$12 depending on what you want. It's comparable to a nice restaurant.
Hope you have a fantastic cruise, and once again, welcome aboard!