International credit cards have pulled out and Russian banks don't dare move in, meaning banknotes and a new system called Pro-100 are the only ways to pay.
Russia's War Against Ukraine
The Guardian: Money crisis in Crimea. How sanctions against Russia have made cash king
A boy holds a Russian flag during a rally marking the one-year anniversary of Crimea voting to leave Ukraine and join the Russian state in central Simferopol on March 16, 2015.