Little is known about the folk ontology of money. Across four studies, we examined how participants classify two important cases: currency artifacts (bills and coins) and ad hoc currency objects, which include artifacts not intended to be currency (e.g. cigarettes) and natural objects (e.g. shells). In all studies, participants reliably categorized shells and cigarettes as money only when they functioned as a currency within the current social system. In contrast, many participants continued to classify currency artifacts as money even when they no longer functioned as currency. Interestingly, responses were bimodal, with participants either fully endorsing or rejecting the classification of defunct currency artifacts as money. When asked to generate properties of money, participants mentioned social (e.g. being a medium of exchange) and physical (e.g. having a serial number) properties, but rated social properties as more important. Participants saw artifacts and social conditions as interacting but placed more weight on social conditions overall. Therefore, data indicated that although participants primarily represented money as a social kind, the intuition that broken or unused artifacts retain their intended kind led people to sometimes classify as money those artifacts that exist in virtue of social conditions.