In 2021, the US Center for Medicare and Medicaid Service mandated the Price Transparency Rule, requiring hospitals to publish a patient service price list called Charge Description Master. However, the mandated machine-readable formats made it difficult for patients to understand pricing and limited price transparency. To address this, we developed the LibreHealth Cost of Care Explorer App to provide patients with a user-friendly format of the CDM. We conducted a mixed-methods user study with 55 patients in two large US cities, one in a safety-net hospital and another in a for-profit hospital, and used PLS-SEM path modeling to analyze the app’s acceptability using the Unified Theory of Acceptance and Use of Technology constructs. Behavioral Intention and Facilitating Conditions significantly impacted Usage Behavior. Effort Expectancy also had a positive impact. Further explanations for the observed model differences in the two hospital systems were obtained from think-aloud observations and semi-structured interviews.