As someone who has been dealing a lot with this (argentinian living in the us for 6 months while the gov. was putting exchange controls every few weeks, going back in 2 weeks for 6 more), let me give you the full picture.
Credit cards:
If it is an international one, it can be used overseas. It will use the official conversion if you buy something in another currency and you can pay the bill in pesos (regulated by several laws, no one can force you to pay in USD). With the latest modification, you will need to pay a 15% on top of that. So, if you buy several stuffs for 1,000 usd, you will see a charge in your credit card bill for those 1000 USD (it depends on the bank, a few ones stopped giving you a detail on USD and it is transformed automatically to ARS) and another one for 720 pesos (150 usd at 4,80). You can also withdrawn USD dolars in a ATM as a cash advance (the amounts were reduced by several banks, but they still work if you need cash). They work over internet and in person.
Debit cards:
Argentina doesn't issue Debit Cards, we use another type called Electronic Debit Card (Visa Electron). The main differences are, it doesn't work over internet (only transactions that you can swipe it), the card doesn't have the numbers/name embossed into the card (it is printed), and you can't overdrawn. You can use it overseas if like I said, you can swipe it. It will use the official conversion rate and it will add on top of that a 15% (because you dont pay a bill, you need to pay that in the moment). You can not withdrawn money from ATMs if you have pesos (only if you have your card linked to a savings account in the bank in USD). Small detail, US systems dont detect this card a a "debit card", so if you buy something from, lets say, CVS, you need to select your card as a "credit card", if not, it will not work even if you swipe it 100 times.
Regarding the 15%, at the moment, the AFIP hasn't updated the regulations so you can pay that amount, but you can't present that information to you employer to pay less taxes (impuesto a las ganancias). Currently the only way to deduct this is to present the form F572 next year, I believe it's in march or something like that. If you dont pay this tax, well.. (insert cricket sounds). Sorry, no way to recover it yet.
Regards,
Chris
