Listen people, AFIP want their cut to make up for the imaginary "official rate". Sell your USD at cuevas and pay in pesos, it is not hard to figure out.
20% applies to everyone
I would not use my credit card, just pay in cash and then AFIP will not be looking at your credit card statement.!!
Yeah but you're assuming everyone has USD to sell. Most people here who are earning pesos are trying to convert them to USD any which way they can and are not willing to sell any unless absolutely desperate. Most peso earners just want to burn through their pesos and hoarde the USD. So since you're getting charge 20% regardless as to whether you pay cash, credit or debit, it doesn't make sense to change USD -- if you're pesos-earning you will have bought your USD at a rate that no longer exists, so when you sell USD now, you can never replace them at the same cost.