Extant research remains equivocal with respect to whether scarcity increases or decreases charitable behaviors. This research suggests a reconciliation by considering a donor's resource-specific scarcity, and their person-thing orientation (PTO), a novel personality variable that determines whether individuals are naturally attuned towards people versus things in their environment. Person-orientation predisposes preferences towards donating time, while thing-orientation predisposes preferences towards donating money. Time scarcity leads person-oriented individuals to prefer donating money, but does not affect thing-oriented individuals. Financial scarcity leads thing-oriented individuals to prefer donating time, but does not affect person-oriented individuals. Person-oriented individuals' attention towards other people and thing-oriented individuals' focus on resource evaluation form the basis for the observed relative donation preferences. Finally, PTO can also be situationally induced. Using donation intentions and real click-through behavior for diverse charitable organizations, we show in five studies that the combined effect of consumers' perceived resource-specific scarcity and PTO determines the relative preference for donating time vs. donating money. Our results have important implications for charities soliciting specific kinds of resources, as well as real-world government and social welfare initiatives critically dependent on volunteerism. Theoretically, we examine scarcity from an individual-difference perspective that has not been well understood. Supplementary information: The online version contains supplementary material available at 10.1007/s11747-023-00938-2.