Prescription Drug Sunshine, Transparency, Accountability and Reporting Act or the Prescription Drug STAR Act This bill establishes requirements for prescription drug manufacturers to provide certain information about pricing, discounts, and product samples of applicable drugs. Specifically, the bill requires the Department of Health and Human Services (HHS) to annually determine whether there are price increases of a certain threshold for outpatient prescription drugs covered under Medicare, excluding low-cost drugs. Manufacturers must provide HHS with an explanation for drug prices that (1) cumulatively increase by at least 10% or $10,000 over one year; (2) cumulatively increase by at least 25% or $25,000 over three years; or (3) are at least $26,000 annually, per individual, if first covered by Medicare during the applicable year. The manufacturer must explain the role of the factors contributing to such prices and other relevant information, including manufacturing costs, marketing costs, and revenue. Additionally, drug manufacturers must provide HHS with aggregate data related to product samples of drugs, devices, biologic products, and medical supplies given to hospitals, physicians, or other medical professionals during the previous calendar year, beginning in 2023. The bill further requires HHS to make publicly available the information related to drug discounts, rebates, and price concessions that is provided annually to HHS by group health plans. Drug manufacturers also must report to HHS certain sales information for drugs available under Medicare for which the manufacturer does not have a rebate agreement in place. The bill requires HHS to study and report on trends concerning inpatient hospital drug costs.