There is a special offer for people who are Carnival Cruise members of their gambling club. Strangely I found I was eligible even though I haven’t been on Carnival in years (maybe 10!). You can go to the carnival.com website and look up your name and birthday to see if you have a membership number and are eligible.
Sign up for cruise by June 28 2018, get Inside or Oceanview on select cruises and sail until 12/31/2020. Looks like it is good up to two cruises (read the fine print). Pay $100 per person, up to two people, get $200 cabin credit back. Plus pay tax and gratuities. Lots of itineraries available, but deposit is non refundable. I priced a 8 day southern cruise at $450ish for an oceanview (obstructed) spa cabin including port tax and you get $200 back, total for 2 people.
I was looking for handicapped cabin and ran into some problems, most are booked for 2018. Found large obstructed oceanview, but it is under the fitness room, which I think would be noisy. I am still looking. Phone people are very helpful.