Ha, I knew it.
Buenos Aires, Argentina in general was cheap, perhaps it still is, but it's not what it was even two year ago. Remember that inflation is running at 20% in the country, and that includes both salaries and prices. Which means that while for people that work in Argentina things have not gotten 20% more expensive (though it seems that way!), for foreigners it has.
$ Peso traded at around 3.20 for a US dollar two or three years ago. With that exchange rate you could get 320 pesos for 100 US dollars, and 'get by' with 50 to 80 pesos a day, food, hotel everything... that's less than 20 dollars a day. That was certainly a bargain, about almost a week on 100!!
Today, you only get less than 3 pesos for a dollar after comissions, and you need at least 100 and likely 150 to buy the exact same food and shelter. So only 200 and something pesos for 100 dollars, and it's probably gone in two days.
By that I'm not saying things are outrageously expensive, but with the relative weakness of the US economy (dollar) compared to the Argentine economy it's just not as cheap anymore.
You should visit anyways, it's worth it not just based on price!!!