The Celtic-speaking town of Lattara (modern Lattes) in Iron Age southern Gaul was an important centre of sustained colonial interaction with Etruscans, Massalian Greeks and Romans from the sixth century B.C. One of the important consequences of these encounters was the introduction of coinage. Through an examination of the archaeological context of coins, I investigate how the use and value of money changed at Lattara after the Roman conquest. Drawing upon several anthropological discussions of money in colonial settings, particularly Jean and John Commaroff's (2006) notion of ‘commensuration’, I suggest that the incorporation of coinage into transaction systems at Lattara was related to its expedience as a standardized form of value, which facilitated exchange between the inhabitants of the town and foreign merchants.