Well I guess you can use your license from your own country. But then never attempt to drive another persons car without a
" Cedula de Identificacion Para Autorizado a Conducir" which is an authorization from the owner of the car for you to drive it. Even if the owner is with you, one must have this card. Or you get a nice fine or worse a huge bribe roadside. You can get one with the owner and you going to the Policia or the Insurance company.
As for the drivers license here, unless you have a DNI, forget it.
Like is said on other posts, it pays to do the right thing. And getting a DNI is very easy, just call this man Gabriel Celano at 4342-9433 in BA,he got mine in 40 days, and it has to be renewed every year for 3 years.
He is honest and does not fleece his clients, unlike a lot of other SOBs.
Buying a car is no problem if you pay cash. But on time you need a DNI.
Oh, one other thing. Your drivers license is valid until you get stopped by one of those nice policia who decides it is not and then your in trouble again, at least dinero wise.