OnStar is a service offered for vehicles made by General Motors. It is a subscription-based service that gives owners a number of connectivity options. The cheapest OnStar subscription tier is Connected Vehicle, which starts at just $24.99 per month. The OnStar Premium subscription is the most expensive as it costs $49.99 per month. The middle tiers of Essentials and Safety & Security cost $39.99 and $29.99 respectively.