You do need to be flexible in the type of ship you are willing to go on. I just am not interested in the older, smaller ships that some companies still have in their fleets (I'm thinking of the Carnival Fantasy class or Royal Caribbean Majesty or Vision classes). Also, when you say last minute, how last minute? I mean, they don't tend to give away cabins even in the last couple days. And the popular ships and times of year, the prices usually go up as sailing approaches.