In the time of Jesus with 200 denarii you could not buy bread for 5000 people.  Caesar's image appears on denarii, the Jewish tribute coin.  In Jesus' parable, the workers in the vineyard each received a denarius for a day's work.  In another parable of Jesus one of the debtors owed the moneylender 500 denarii.  In another parable the king's steward had a debtor who owed him 100 denarii.