Ola Amigo !

Since you have a CPF, there should not be a problem.

RIO: = Oi, or Claro are best there. We also purchased ours at Lojas AM, which took all of 13 minutes to buy, and activate.

The Skype suggestion works well, too.

Which one is cheaper ? Hah ! Even a single Coxinha cost these days.
You're in Brasil my friend, the new economic Superpower with European prices !