What everyone said above.
Argentina is a strange place to live when it comes to finances. You may not realize, for example, that those same cards that are offering deals at stores all throughout the city (I'm assuming in other cities/provinces as well) interest-free monthly payments for up to a year (depends on product, store, etc). As I understand it, it is a requirement by law that the banks offer this. No one would be crazy enough to offer interest-free payments in a climate of such high inflation unless they were forced to. But you can leverage such things to make a really good deal for yourself if you buy, for example, appliances on 12 payments and watch as the price of the item increases 30% over the year while you're paying the value of the loan you started with! Quite unlike the new car business (check out the other thread posted today by Gringoboy)