Based on ethnographic fieldwork with panhandlers who provide services while asking for money, informal interviews with pedestrians who have interacted with them, and formal interviews with twenty people who regularly interact with panhandlers, this article unpacks the relationship between temporality and ambiguity of meaning in exchange. In line with previous research, I find that providing a service while asking for money allows panhandlers to manage stigma by recasting their relationship with pedestrians who give as a market exchange. More surprisingly, I (...) find that this kind of recasting makes giving less compelling for the pedestrians in fleeting encounters with panhandlers: they resist service provision in fleeting encounters with panhandlers on the grounds that the exchange is experienced as a coldly rational quid pro quo. In contrast, pedestrians who have long-term relationships with panhandlers experience the interaction as a gift exchange and the service as an expression of gratitude and subservience. The development of an open-ended temporal horizon and of a cycle of exchange, I argue, allows the service and the money given to operate as boundary objects, enabling panhandlers and pedestrians to attach different meanings to the exchange of money for services. This emergent ambiguity allows them to carry out interaction and exchange successfully. Contrary to models of interaction and everyday economic transactions that frame shared definitions of the situation as necessary for successful and repeated interactions, I find that ambiguity and polysemy may be productive and sustaining in interactions between participants from distinct social worlds. (shrink)