Original Medicare is designed to help with the cost of certain medical and hospital procedures, but it does leave out some essential supplies and services you may need. This is where Medicare Supplement insurance (Medigap) can come in handy.
Original Medicare consists of Medicare Part A and B, which have out-of-pocket costs you take care of – co-insurance, co-payments and deductibles. Medigap is designed to cover these costs, at least a portion of them.

47 states offer some kind of letter designation or Medigap (such as Plan M). Minnesota, Massachusetts, and Wisconsin have developed their own standardized plans, but the premise is the same no matter the designation. The idea is to cover costs Original Medicare fails to cover.