busy girl-Let me first begin by welcoming you to cruise-chat! This is a wonderful place to visit and share all things cruise related and other thoughts! We learn from each other here,save each other from the landlubbers and are able to be at sea in our hopes and dreams even while sitting at home! If you can't be at sea-come visit us here-it will ease the pain!
I have never been on a ship where alchohol drink cards were offered. Usually I travel on the mainstream cruiselines (RCCL,NCL,Carnival), but I have done Cunard,Chandris and others too! Soda cards are a good idea,especially if you have children or are a soda addict. Certain cruise lines (i.e. Carnival) offer alchohol drink coupons thru their web site or cruise amenities office in advance of the cruise. However-if the drink is a specialty drink or a drink other than from the bartender's "well" (i.e. his basic liquor stock ) the additional fee will be charged to your ship charge card.
I hope this answers your question and I wish I were incorrect but for most of us-we still have to pay for our drinks on a per cocktail basis!