Hi Synthia,
You can probably retire on $1000 a month in Argentina, but probably not so easily in Buenos Aires. In the city where I live, we have beaches, English cable, high speed internet, nice weather, and 1 bed apartments for about $250 per month. Utility bills are very low in comparison to the USA and Europe. There is also a good medical structure and we (a family of five) have a top plan and pay 400 pesos a month ($130).
The most important aspect, is that everything is in walking distance - saying that, taxis are extremely cheap and we hop in and out of them. Comparing BA to Mar del Plata, the restaurants and entertainment here are definately much cheaper and the same can be said for real estate.
If you would like more information, I do have a personal website