Sao Paolo is not itself a cruise port, but is served by the port of Santos. Added up, the port of Santos functions as the point of embarkation for about forty cruises anually from both MSC and Costa to South America, along with other places.
On average Sao Paolo is somewhat inexpensive compared to other ports. Sailings departing from Sao Paolo during the the peak season of winter are much more expensive than the the low season of spring. The chart below shows the monthly average cost per day for cruises from Sao Paolo (Cruises only depart from Sao Paolo between January and April).