The smallest coins in circulation in Judea at the time of Christ were tiny bronze affairs that had been struck by the Maccabean or Hashmonean kings a century before.
These come in several varieties. One common one has the Hebrew inscription "Yahonatan the High Priest and the Council of the Jews" within a wreath on the front and a cornucopia adorned with ribbons on the back.
The lepton or half-prutah was an inconsequential amount of money. It took 32 of them to buy a loaf of bread.