Soda package was @$25 for the 4 night criuse to Cork from Southampton which has to be bought on the first day! We bought one and used it between us

Can't comment on the wine package, as we didn't get one!
On board prices are all in $, only when going off the ship you'll need euros.
Beer on board ranges from $6 - $9.50, again can't comment on spirits prices!
one thing to note is that you may have an onboard allowance, depending on how you booked, on our last criuse we got $50 per stateroom, this time we will recieve $200 (sailing in May 2009 to Cork).
These prices may well have changed since the £ as weakened, otherwise alcohol is going to be expensive

Rob.