Oddly enough, for as expensive as they are, I found
DCL the easiest to discount due to the discounted gift cards. For the last one I worked Swagbucks to earn extra "free" money (just took time) and used the sales and whatnot to discount what we did buy. I'll have to check the sheet but I thought we hit at least 30% on that one. I probably wouldn't recommend Swagbucks at the moment because it's not as easy to earn quickly right now but any type of program like that would help.
Best strategy is usually opening day pricing. There is such high demand for DCL, prices really don't go down as a rule. There's always exceptions but very rarely. If a sailing isn't selling as well as they like they do put out specials, but they aren't usually better than opening day, but can be close. Sometimes you get last minute pricing but it doesn't happen for every sailing so it's a gamble if you have limited dates. That's the *GT rates people talk about.
This article hits the highlights of IGT/OGT/VGT rates. They guarantee you'll get a stateroom in at least that class you book but it could be anything within that class. Just ignore point #3 and don't limit yourself to Target for point #4
https://www.wdwinfo.com/disney-crui...money-on-your-disney-cruise-line-vacation.htm