We just found out that the rules for getting your DNI have changed. You now need either proof of a pension income or an investment of 1.5 million pesos to qualify for your DNI! That means a major real estate or business investment if you are a younger person hoping to live here without a pension.
Argentina's government is constantly changing the rules for foreigners. It is now more difficult to stay in the country without your DNI, and more costly. On a tourist visa, one has to leave the country every 3 months. We were recently stopped in NY because we didn't have our DNI and didn't have a return airline ticket. (We do own property in Argentina and we were returning home via the U.S. on that trip.)
So, be advised that the government is no longer free and easy with extensions of the tourist visa, and it is much harder now to qualify for the DNI.