It's true what people are saying about the prices of food, etc. Many of the published articles are using far outdated information as a basis but it has no bearing on reality anymore. In a "cheap" supermarket in my non-tourist neighborhood, a package of 3 skinless chicken breasts costs a minimum of $30 pesos. I saw a whole rotisserie chicken the other day going for $75 pesos (when I used to be in a rush to cook I'd occasionally buy one but for $25 pesos). one sheet of fresh raviolis costs $12 pesos. Some vegetables and fruits are inexpensive (6 pesos for a kilo of bananas or tomatoes), but you'd be surprised by the costs of some average pantry staples. A can of tomatoes costs $6 pesos, and a can of refried beans these days (an import, Argentines don't eat refried beans typically) now costs $17 pesos in the stores (when I arrived in 2006 we could get cans for $4-6 pesos). Things are more expensive by at least a couple of pesos/item in the more touristic neighborhoods which is where you'll be more likely to find temporary/shared housing. Everything has at least doubled in price since I have arrived, some things have tripled or more. You'd best be careful about your calculations about food, it really is equivalent or more expensive than in the States. I can personally vouch for that. Additionally, I hear Europeans all the time saying how cheap places like Berlin, Amsterdam, and even Japan, etc., are in comparison.
Also, it's important to know that many walk around and see ANY tourist/foreigner (it doesn't matter who you are or what your intentions are) as a walking ATM to be taken advantage of. It takes awhile to learn the ropes and figure out how to get around that, but it still happens occasionally even to me in a neighborhood (again, non-touristy) where I've lived for a couple of years.
What everybody else is saying about pollution, garbage in the streets, corruption, etc., is also true. It's very eye opening. That's not to say you shouldn't come, but you seem pretty idealistic about what life is like here, and... well, I guess you'll figure out where the truth lies when you arrive.