The US fee-for-service payment system under-reimburses clinics offering access to comprehensive treatments for opioid use disorder (OUD). The funding shortfall limits a clinic’s ability to expand and improve access, especially for socially marginalized patients with OUD. New payment models, however, should reflect the high variation in cost for using a clinic’s clinical and voluntary psychosocial and recovery support services. The authors applied time-driven activity-based costing, a patient-level, micro-costing approach, to estimate the cost at an outpatient clinic that delivers medication for opiate used disorder (MOUD) and voluntary psychosocial and recovery support services. Much of the cost variation could be explained by classifying patients into three archetypes: (1) light touch (1–3 visits): no significant co-occurring psychiatric illness, stable housing, and easy to connect for ongoing OUD treatment in a traditional outpatient setting; (2) standard (average of 8 visits): initially requires an integrated team-based care model but soon stabilizes for transition to community-based outpatient care; (3) quad morbidity (> 20 visits): multiple co-occurring substance use disorders, unhoused, co-occurring medical and psychiatric complexity, and limited social supports. With the cost of the initial visit set at an indexed value of 100, an average light touch patient had a cost of 352, a standard patient was 718, and a quad morbidity patient was 1701. The cost structure revealed by this analysis provides the foundation for alternative payment models that would enable new MOUD clinics, staffed with multi-disciplinary care teams, and located for convenient access by high-risk patients, to be established and sustained.