Hope not $15 per drink.You may want to look at hollan for your next cruise where they have two for one at the pool bar during happy hr.Allships need to do something to encourage more drink consumption anhd they might just increase their profits.The prices now charged are way out of line.
I called RCL and asked, and there is no card or program for alcholic drinks. There is, however, a wine package for 7-night or longer cruises. Inquire at the dining room on your first night. I did read a review though that it wasn't suggested because the traveller really didn't save any money with the package (when he considered the individual prices).