Presidential candidate Hillary Clinton has indicated interest in a Medicare buy-in option for those ages 55 to 64 and a public plan option for the Affordable Care Act’s Marketplaces as mechanisms for increasing the affordability of insurance outside employer-sponsored insurance. Medicare is an attractive basis for developing insurance alternatives (either a direct buy-in or a public option based in Medicare rates) since the program generally has lower provider payment rates and lower administrative costs than private insurers. This paper explores the design issues raised by these proposals and their implications for costs and benefits to different age groups.