Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Puerto Iguazú (60% of total searches to Parana River). The next most popular destinations are Foz do Iguaçu (31%) and Corrientes (5%). Searches for hotels in Santa Fe (3%) are also popular.
KAYAK users have found double rooms in Parana River for as cheap as $12 (Rosario) in the last 3 days. The average price is $99.