1) Yes, the cities in the interior are cheaper, even Rosario and Cordoba.I often take the train to the coast and pass through these towns - ugly, run down buildings that haven't been painted in fifty years or more, gnarled tree trunks painted white, untidy plazas, stray dogs, piles of rusting junk all over the place, usually not a single cafe or restaurant in town. What expat would want to live this way? And who would s/he talk to? Are the cities -- Rosario, Cordoba, Salta so much cheaper? I have my doubts.
2) The cities of the Buenos Aires, Cordoba and Santa Fe province are generally nice places: Villa Maria, Junin, Pergamino, etc etc etc, and look better than most of Buenos Aires (which cities do you pass while going to the Atlantic beaches? Dolores?)
3) The cities of 70.000-150.000 inhabitants have a lot of infraestructure, maybe even malls and cinemas (Alta Gracia for example, 45.000 people I think, cinemas,casino, nightclubs, dozens of restaurants, and 40 minutes from Cordoba, amazing lifestyle chances,and yes, expensive, but never like BA).
Obviously, you don´t know Argentina (remember, the soja brought a lot of money to the interior).