In Brazil a $ goes a bit further than in the US.
(Big Mac index, http://www.oanda.com/currency/big-mac-index)
Jokes aside, in Brazil you need ~$1000/month to live* in a big city, ~$700 in a smaller one, ~$500 as a broken college student.
(live* as in small apartment, internet, public transportation, entertainment but no luxury).
I lived in an apartment off the beach in Praia Grande for a few months. Rent was about R$650 (~$300 US) for a little 2 bedroom.
I met a number of people who lived on less than R$300/mo (granted, that was in some of the poorer areas).
Lunch in the financial district (where I spent about a year) was ~R$10 (for a pretty good lunch - chicken, rice, vegetables, and a drink). Most American fast food restaurants, however, had prices comparable to the US (McDonald's dollar menu items were about R$2.50, it was R$30 for a pizza at Pizza Hut, etc).