As part of their strategies to increase college readiness and reduce educational inequalities, at least 29 states subsidize Advanced Placement (AP) exam fees for low-income students. However, while Michigan’s state-level policy subsidized low-income student exams to $5 per exam, we found wide-ranging fee structures at high schools—from $0 to $50. Through a lens of policy implementation theory and using an embedded case study approach, this study examined this disjuncture between the state and school policies using interview data from 33 school personnel—counselors, AP Coordinators, administrators—in 31 high schools and state personnel in Michigan; state policy artifacts; and publicly available school data. We identified three major challenges—many schools hedged and set higher fees because they were unsure how much the legislature would approve each year; the state subsidy did not account for additional exam costs (e.g., exam proctors) that were passed down to the student; and the policy as written lacked enforceability and accountability. Policymakers were largely unaware of the amount schools ultimately charged low-income students. In the presence of an ambiguous policy and constrained resources, school personnel relied on their personal perspectives on fees and behavior (e.g., the need to reduce moral hazard and increase “skin in the game”) to rationalize low-income students fees. Together, these findings help explain how low-income students pay vastly different AP exam fees depending on the high school they attend in Michigan—with some schools severely impeding low-income students’ college preparatory opportunities.