Healthy Montana Kids (HMK) Children’s Health Insurance Plan is a Montana Healthcare Program offering free or low-cost health insurance to Montana children up to age 19. Covered services include medical, dental, eyeglasses, and other related services.  Medical benefits are largely administered through the Blue Cross Blue Shield (BCBS) of Montana Provider Network. Treatments and services must be medically necessary and the member must be enrolled at the time the service is delivered.