USD, greenbacks. $$$$$
I am not dissing the Argentine schools because they are actually pretty good, however, it is one thing to toss your kid into the culture and quite another if you expect him to do calculus or history in a non-native language. These are things that have much to do with the childs age, ie if the kid is only 4 or 5 then language isn't going to slow them down much.........at 14 or 15 it's another story. [at 4 or 5 years a child picks up language like a sponge]
There are many other Argentine private schools, and German and British. The Argentine privates cost much less. However, Lincoln and BAICA prepare the students for the PSATs and the SATs etc and they run on the US school year. Parents here that have their eye on UCLA or similar find this to be an advantage.
If you suspect that your child will head back to the US for College, then you must consider this. If you are unsure, then, these schools also provide a "Polymodal" program that will help the child attend a local university. [have it both ways, you need to remember that the little angels collect girlfriends along the way and then good old UCLA is off the map and UBA is dead center]