Motorists in socialist Venezuela have long enjoyed the world's cheapest gasoline, with fuel so heavily subsidized that a full tank these days costs a tiny fraction of a U.S. penny. Bartering at the pump has taken off as hyperinflation makes Venezuela's paper currency, the bolivar, hard to find and renders some denominations all but worthless, so that nobody will accept them. Without cash in their wallets, drivers often hand gas station attendants a bag of rice, cooking oil or whatever is within reach.