Currently, September is the cheapest month in which you can book a flight from Lexington to Sao Paulo Guarulhos Intl Airport (average of $678). Flying from Lexington to Sao Paulo Guarulhos Intl Airport in December is currently the most expensive (average of $1,209). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.