This study compares the effectiveness of three post—acute adolescent substance use treatment programs: Outdoor Behavioral Healthcare (OBH), Treatment As Usual (TAU), and no structured treatment (NST). The target population were aged 13–17 with substance use and mental health issues. Assuming 100% completion, program costs per person were $45,260 for TAU and $28,274 for OBH. Costs adjusted for actual completion rates of 94% in OBH and 37% in TAU, were $0 for NST, $27,426 for OBH and $31,113 for TAU. In the latter, OBH had cost-benefit ratios 60.4% higher for emergency room/inpatient, increased life span, and societal benefits; and 424% better for parental reported health outcomes. These findings should be of great interest to insurance companies, healthcare advocates, treatment program providers, and clients in need of post-acute services in the changes occurring in the current Parity era.