mattman:
Extremely cheap!
It makes you wonder about the quality of the onboard service, but still a good find for someone wanting to get to South America for peanuts
Looks like the ships go to SA to do 3/4 night booze cruises over the winter.
Rather than sail empty on the TA get people on the ship to spend and pay the tips(crew wages)
The incrimental cost to the cruiseline of a passenger is very low this cost will just about cover those.
MSC do get mixed reviews and are very much a european cruise line so not for every one.