Hey I'm little delaying on posting here but it doesn't mean that nothing happened. I've search internet and I've found a lot of stuff about cost of life in Rio de Janeiro. Is it full of shits about middle class life and maintaining living standards etc. I just want to say if you want to come to Brazil and you don't have to enough money, you have to accept the fact that you will LOSE your life standards. And besides Brazil doesn't offer the same things as Europe offers.
And other thing, if you're afraid that you will lose something you should probably stay at home. Leaving your country you will lose so much that you expect. It's like some people want to start a business and don't have balls for losing money. It will always lead to hell.
In Rio de Janeiro is a huge difference between poor and rich people. The poorest live in shacks. The most rich people lives in 500m2 penthouses with spectacular view. But don't be confused almost all the slums are located on hills and it's giving an advantage. You can get a spectacular view for less price. But probably the asphalt road won't be in front of your house.
If you want to rent small apartment in Copacabana or Leblon, you'll pay something around 1.300 BRL. But you'll need Brazilian guarantor if you never had a rented apps in Brazil. In Rocinha the price for small "house" is around 500 BRL and you'll get 2 bedrooms, living room and kitchen. Usually unfurnished.
Let's say that you don't need too much electric devices and in that case you'll consume something around 50 BRL per month. Water consumption for 2 people is around 30 BRL. Water in Rocinha is for free but the quality is questionable (a little bit stinky).
Price of internet in Rio is around 30 BRL. The provider NET has for that price 10 Mbps. In Rocinha is that price for 700-1000 kbps.
Food depends on your personal desires and needs :D If you're fat pig that eats every 30 minutes you need a lot of money. But I think in low cost version is about 200 BRL if you prepare food in your house. Eating on street is quite expensive. I guess 30 BRL per day in low cost version.
OK comparing this expenses with a minimal wage in Rio de Janeiro 630 BRL it seems that life is impossible here :)