score:5
If you don't have time restriction then I'd suggest to get Schengen visa and travel most of the way in Europe by land.
In Europe you can find really cheap night long distance buses (even starting from 1 EUR if you booking in advance, have some patience and a good luck) ,and this lets you don't pay for hostel. Blablacar is also much cheaper than flights.
I have no experience in South America, so cannot say about that part.
Right now I see $430 from Salvador (Brasilia) to Valencia, whilst Buenos-Aires to Moscow is ~$800.
For the same time period: Brigetown-Kaunas $388 (check visas!) Sao-Paulo-Valencia $346 Sao-Paulo-Moscow $513
Upvote:5
We've used Moscow-Dubai, Dubai-Rio-Buenos Aires route using Emirates I believe and price was tolerable as these things go - ~35 000 rub one way per person a year ago. Our return flight was from Peru and considerably more expensive (900 euro/person via Panama and Frankfurt)
Via skyscanner I believe.