Sao Paolo isn't actually a cruise port, but is served by the port of Santos. Combined, Santos is the port of departure for only twenty cruises per year from both MSC and Costa to, along with other places.
Prices are roughly equal throughout the year. On average sailings from Sao Paolo are extremely inexpensive compared to other ports. Take a look at the chart below for the average cost per day by month (Cruises only depart from Sao Paolo between March and April).
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