If you qualify for a subsidy
HealthCare.gov is the most affordable coverage available, full stop. Medicaid is expanded (Healthy Michigan Plan) in Michigan.
If you don't
Full-price marketplace plans are the most expensive coverage in Michigan. For healthy people, private PPOs on Cigna, Aetna and PHCS PPO are routinely 30–50% less. Michigan has no state individual mandate.
What's not affordable
Health-sharing ministries and indemnity plans look cheap until you have a claim. Ask for the out-of-pocket maximum; if there isn't one, it isn't insurance.
Michigan has a deep self-employed and skilled-trades workforce, and Blue Cross Blue Shield of Michigan dominates the marketplace — which is why people who want a different network look at private PPOs.