Hi, I used to work for Carnival Cruise lines and a few tips are: They do very little for honeymooners for free (a cake and congratulations on one of the formal nights) anything more must be purchased. When considering the cost keep in mind that there are lots of hidden costs in cruising, including tipping, photos, drinks,excursions and much much more. we cruised for free and it still ended up being quite expensive. The travel/cruise insurance is worth every penny, I saw many people regret not purchasing it. Also make sure you're on a cruise geared more for adults, days at sea with many screaming kids can really kill the mood! I reccomend Norwegian Cruise Line, they have free style cruising perfect for honeymooners. Also you can request Cruise dollars instead of a gift registry in your invitations where your guests can call the cruise line and give a credit card with a dollar amount to be added to your onboard acct.
One more tip... the word BOAT is a four letter word in the cruise industry, you'll be on a Ship
Best wishes,
Frosty