Student health insurance is offered as a low cost alternative because not everyone can afford expensive individual health insurance.

If your family is insured under an HMO Plan, the policy may not extend primary care treatment to a family member who is away from home.

Purchasing student health insurance can fill in the gaps since your parent's policy may not pay 100% of medical costs, limiting out of pocket expenses for costly medical treatment. Also, coverage through your parent's policy often includes a provision that once a dependent family member becomes of a certain age, this member is no longer eligible for the plan.