Disney Cruises offer unbeatable family fun. The popular line is well-known for its excellent kids' programs, live entertainment and gourmet dining. However, cruising with Mickey, Minnie and the rest of the Disney pals doesn't always come cheap. Fortunately, there are ways to save on cruises to Disney's private island, Castaway Cay, and other tropical Bahamian ports. The key to preserving your budget is to know where and when to shop.