Argentina has an international departure tax of $18, payable by credit card or in cash in pesos, dollars, or euros. There's an $8 domestic departure tax, but this is often included in the price of tickets. Hotel rooms carry a 21% tax. Cheaper hotels and hostels tend to include this in their quoted rates; more expensive hotels add it to your bill.
Argentina has 21% V.A.T. (known as IVA) on most consumer goods and services. The tax is usually included in the price of goods and noted on your receipt. You can get nearly all the IVA back on locally manufactured goods if you spend more than 70 pesos at stores displaying a duty-free sign. You're given a Global Refund check to the value of the IVA, which you get stamped by customs at the airport, and can then cash in at the clearly signed tax refund booths. Allow an extra hour to get this done.
Global Blue (11/5238–1970. www.globalblue.com.)