Hi there,
Moving around in Brazil is fairly accessible, but domestic flights in Brazil are not cheap when compared against the flights into Brazil.
If you want to see anything of the country, you"ll need to take at least one domestic flight as Brazil is a large country.
If you are looking to do extensive travel in
Brazil, I would
recommend buying a Brazil Airpass, from Varig or Tam as part of your overall ticket price for your international flight to Brazil.