Thank you already for your replies!
It seems still not to be clear what is best, but as we start in Euro, it's maybe not necessary to change in dollars before buying pesos. As someone wrote, we will also lose money through the exchange Euro to Dollars.
Is it also easy to find places to exchange outside a bank in other towns? Like Salta or Bariloche?
And then a related question: When trying to pay with a credit card, I noticed that some places accept only a Visa card. Is this common, or are Mastercards also accepted?Tx