A perioikos (peri = around, pikos dwelling, plural perioiki) was a free inhabitants in the Spartan territory of Laconia, who was not a Spartan citizen. The perioiki were obliged to give military service in defence of Laconia when called up.
The spartan economy did not have coins, but they used iron bars to give value. The Spartans were not big on trade, so they conquered neighboring lands to get food and supplies. Helots-captuered slaves-did a lot of dirty work.