20 Pesos

Argentina's provincial quasi-currency experiment — the so-called "patacones" and their regional equivalents — emerged from the catastrophic 2001–2002 economic collapse, when the federal government froze bank accounts and the country effectively ran out of hard currency for day-to-day commerce. La Rioja was among the provinces that had already been issuing its own parallel scrip, the Petrom, for years before the national crisis hit, making it better positioned than most to expand circulation when the peso became functionally useless.

These provincial notes were legally denominated in pesos but redeemable only against future tax obligations, a mechanism that blurred the line between currency and government IOU. By 2003, federal stabilization had resumed and most provinces were under pressure to withdraw their scrip — this issue dates to that unwinding phase.