Medicare at 50 Act This bill establishes a Medicare buy-in option for certain qualifying individuals and also repeals restrictions relating to prescription drug prices under the Medicare prescription drug benefit. Specifically, the bill allows individuals aged 50 to 64 to enroll in Medicare if such individuals would otherwise qualify for Medicare at the age of 65. The Centers for Medicare & Medicaid Services (CMS) must determine enrollment periods and set premiums for the buy-in option established under the bill, in accordance with specified requirements. The CMS must also award grants to states and nonprofit organizations for outreach and enrollment activities relating to the buy-in option. The bill also repeals provisions that prohibit the CMS from negotiating the prices of prescription drugs or from establishing a formulary under the Medicare prescription drug benefit.