Besides sipbroker free access number in Salvador/Brazil you will not find any free DID. Brazil is just starting the VoIP revolution, with just a few legal and experimental local companies. Maybe you can find some very cheap DID (for you, due to currency rate) if you buy the service directly here, from the brazilian provider.
Almost all Brazilian providers are here:
Canal VoIP - ConvergĂȘncia Digital
Seems that
www.tmais.com.br have it.
Good luck!