From the Princess web site:
"...passengers are permitted to bring one bottle of wine and/or champagne per person purchased in a shoreside location onboard. If the wine and/or champagne is brought to the dining room for consumption, a $15.00 per bottle corkage fee will be applied to the passenger's shipboard account. We prefer that passengers bring wine/champagne no larger than 750ml, however, magnums are acceptable. Wine in a box is not encouraged."
Here's the link: FAQ: Cruise Answer Place : Onboard Experience : Princess Cruises
Here's the link to the Princess Cellar's wine & beer packages: Princess Cellars : Princess Cruises
Hope you find what you're looking for