I did this my first trip into BA a few years ago. The driver was waiting for me just inside the country and Jorge proved to be a great guy. He even helped me fill in some vocabulary that I forgot or never learned in Spanish class. Now I know them forever. Same price of US$17. No extra for the language coaching, either.

Later, I learned that the Manuel Tienda León Coach (like a Greyhound) was only about US$3 from their bus station about 12 minutes from my hotel (on foot). Hey, I walk farther than that in most airports. So for my next 5 trips to/from EZE, I just took the coach and sat back and enjoyed the savings.

Enjoy BA!