I wouldn't worry too much about carrying on more than a few sodas and drinks. Most cruises include tea, juice of some kind, and water. So unless you drink alot of soda you can just buy one at any of the bars, or eateries onboard for about 2-2.250 each. I however drink enough soda that it is actually worth it for me to buy the soda package. they can be purchased when booking , or you can usually buy them at the bars, while i probably drink just enough(4-5 sodas a day)to make it economical, there is also the ease of just showing your sea pass than to have to dig out cash, or adding it to your sea pass..
And i guess if you drink alcohol, you can also have it delivered to your room pre embarkation if you order it beforehand i have heard...and apparently it isn't much more than what you would pay for it off ship(except maybe in mexico)lol....
