I went through this process in recent months. I went to the US Embassy to get the fingerprints cards so I didn't need to print them out. I asked for two cards, just in case. So I got the fingerprints done at my local police station in Nuñez and it was fast and easy. I made sure they did the rolled prints and not just the flat prints. Also, I asked that they put a stamp on top of their signature which was no problem. I sent the two completed fingerprints cards to the FBI in case there was a problem with any of my prints. I just sent it in the regular Correo mail system and my credit card was charged by the FBI about 5-6 weeks later. The results were sent to my mom and she then sent them to the State Department in DC for the apostille. The FBI report was $18 and I believe the State Dep. apostille was around $8. She sent it to me (2 papers) and I had it translated here in BsAs. Total translation cost for the 2 papers, including the certification that the translation was correct was around 365 pesos. My appointment at migraciones was fairly straightforward and like others, they told me it would be about 30-90 days until I receive my DNI in the mail. Also, beforehand I questioned whether or not my passport needed to be translated and it did NOT need to be. It's one of the newer US passports with titles in English and Spanish on the main page with picture.