To confirm what others have said, when I got here and was heading up to Brasil I went to the Stambulian who charged me 100 pesos (this was 4 years ago, so probably 400 now), just to explain what a yellow fever jab was and why I needed it. He then said that while they could do it there I wouldn't have the International Certificate so told me to go to Huergo, which I did and it was free. So, basically he charged me to give me an address.