Forget about living in Brazil during the WC with less than 3000€ for the month.
Most hostel/guesthouses are already being booked up. Prices have gone up, sometimes by 3. You'll be lucky to find anything under 50€ a night. That's already 1500€ taken on accomodation alone. Transport costs will go through the roof too. Food is probably the only thing you will still find reasonable. I am guessing that if you wanna be there it's to watch a couple of games (tickets prices $$$$) and celebrate with your fellow countrymen and/or other nationals, which means beers+
If the main purpose of your trip is to travel and see the world, I would skip Brazil altogether during the world cup, you can always go back later, and watch the tournament in another football-passionate south american country like Colombia, which - at the moment - still stands a chance of qualifying.
Edit: Oh and Belgium will win it :)
Edited by: pepfcb