Since Stack’s (1974) landmark ethnography of kin support in a close-knit group of poor black mothers in the Midwest, there has been ample research on social support among low-income black families. While this body of work has largely painted a picture of the cohesive and supportive nature of families in black communities, recent research has highlighted the limited nature of kin support, especially the support available to low-income black mothers. Much of this work, however, has focused primarily on urban black mothers and paid less attention to the conditions that poor rural black mothers face when seeking and giving family support. Using longitudinal ethnographic data from a sample of 16 low-income black mothers in the rural South, we draw on social exchange, negotiated-order, and social capital perspectives to scrutinize the nature and costs of kin support in family networks marked by limited resources, instability, and chronic need. Our findings reveal the centrality of problematic resources and unpredictable family networks as conditions that diminish mothers’ autonomy and compromise important “side bets” as mothers seek out, manage, and repay support. Implications of this study for theories of social support and social capital are also discussed.