The vow renewal costs around $1,100. This includes officiant (I hope the captain), a cake, and a certificate. Perhaps more, but I can't remember right now. Pretty pricey just to say "I do again"!!
I'd have to remarry first before worrying about renewing, and I have as yet to meet someone distasteful enough to even consider inflicting myself on for the balance of a lifetime... That said, there is an alternative to spending so much money on a vow renewal.
Plan on having a private ceremony on the deck 7 secret verandah. Invite Disers in advance. If you have an older child(ren) who will be accompanying you on the cruise, allow them to officiate. If not, ask a CM you are fond of. Or, ask a Diser. Heck, I think it would be an honor to officiate a couple's vow renewal ceremony aboard ship.
Flowers? No problem. Contact Shirley at The Perfect Gift and tell her your plans. I am sure the dear woman can create a most superb wedding arrangement.
Food? Even less of a problem. Order room service for the deck 7 secret verandah in advance. A few cheese platters, fresh fruit, sandwiches, uncooked white rice (well, maybe you should bring your own) and whatever else is available.
Drinks? See "Shirley at The Perfect Gift" above.
Bring your own champagne for a toast and your done. Oh, wait. Music! See if you can "rent" a "dueling" pianist. If not, you can always tape the appropriate music in advance and simply bring along a tape player...