It depends upon the server that you get. I was with friends who purchased a bunch of drink coupons before they cruised. The coupons have price limits printed on them, so some drinks take two. Some servers would request two, some just one for the more expensive drinks like martinis. I have done the math, and for what I drink (beer and liquor), they aren't a money saving perk, but you don't have to sign the ticket with them. I think in the end they probably average out to what you would pay without them for many people (except for me - cheaper not to buy them).