A new economic analysis in Addiction Science & Clinical Practice estimated that preventing HIV among sexual and gender minorities with substance use disorders via Los Angeles County’s A.S.K.-PrEP community program could cost far less than many public health agencies assume. The bottom-up microcosting approach translated program components and navigation services into a detailed per-person cost estimate. The modeling is particularly relevant because prevention strategies for high-risk populations often face funding constraints and affordability questions, especially where navigation and engagement services are required to sustain adherence. A localized cost structure can influence procurement, budgeting, and policy decisions even when trial efficacy is already established. By focusing on optimization within a specific delivery model, the work provides actionable budget inputs for commissioners considering how to scale PrEP support for underserved, high-barrier populations.