Years ago the first night's drinks were free but not in years have they been. If you go to the Captains cocktail party the drinks are free, the same as the past cruisers party (by invitation) and sometimes in the casinos they'll run an hour of free drinks - check your carnival capers for the times.
My husband & I took the Catamaran shore excursion to Dunn's River Falls, which was beautiful, and we were offered MUCHO free Rum Punch on the trip back! With the beautiful sunshine, the cultural music, dancing & that delicious pink drink, it became Pum Runch by the time we returned! We drink very rarely, so we certainly were affected by it, but had a great time...after all, we were on Vacation!