At this moment some good options from Europe to Brazil based on various carriers are available. Consider service of Air Europe, TAP Portugal, TAM or KLM / Air France to book cheap return flights from various European countries to Brazil now already from €385! The cheapest options are round trip flights from Portugal (Lisbon, Porto), Brussels or Luxembourg to Sao Paulo or Rio de Janeiro. With TAM airlines you may consider to fly from various main airports in Germany (Frankfurt) to Rio de Janeiro, Fortaleza, Porto Alegre, Brasilia, Natal and probably more.. 
Travel options vary by each origin and airline but in general you may find these flights to Brazil between November 2015 till March 2016. To check the cheapest connection possibilities we recommend to use service of Skyscanner. This tool gives you quickly an idea which low-cost airlines are connecting Prague or Madrid from your hometown.
To book the cheapest flights to South America you have to look for limited travel options between 1st of March till 24th of March 2015. You may either consider to book double open-jaw flights or for just slightly higher fare open-jaw ticket Prague - Rio de Janeiro - Madrid.
Booking samples
Germany to Brazil based on TAM (please choose Skyscanner DE to find the lowest fare available)
Booking sample of cheap flights to South America from Europe for €385 here. In this case you would be departing from Prague to Sao Paulo on 2nd of March. Your return flight from Rio de Janeiro back to Madrid would take place on 16th of March 2015.
