Well .. from what I have found, gear is available in most of those countries by just walking into a pharmacy and buying it OTC. They have thier own local brands that are much cheaper than say schering or Organon. And I mean MUCH cheaper. Organon, and whatnot are extrememly expensive down there.
Agrentina, Paraguay, and Ecuador seem to be the easiest. Gear is not OTC in Brazil, although there are places that will still sell it to you. All ancillaries and supps are. Lots of gear in SA comes from Argentina, and a lot of it is Vet gear. Some big brands are Dispert, Chinfield, Burnett, Biosano etc..
Planning a trip down or what?