OK, let's start here: The price of the cruise is what the price is on the website when you go to book it.
Once a certain percentage of room within a specific category has been "sold", the category goes "GTY" (guaranteed). That is, you can still book a room in that category, just not a specific one and DCL will assign you a room within your category (or higher) at a later date. The price is the same as if you selected a specific room.
If a cruise isn't selling well, generally after the Paid In Full date, DCL will offer last minute restricted fares: IGT (Inside room); OGT (Oceanview room); or VGT (Verandah room). These must be paid in full at booking, and are for a type of room, not a category. The prices are generally lower than the prevailing price for that same room. Again, DCL will assign you a room of the type you booked (or higher) at a later date.
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!