Unfortunately, you cannot buy SilverSneakers outside of a health plan. The only way to enroll is through a private insurance company with a Medicare Supplement or Medicare Advantage plan. If you do not have one of these insurance plans, you will not be able to join SilverSneakers. However, there may be other fitness programs or gym memberships that are available to you. It’s worth checking with your local gym or community center to see if they offer any programs that are suitable for your needs. Additionally, there are many online resources and apps that offer fitness programs and workout routines that you can do from home.