If you qualify for a subsidy
HealthCare.gov is the most affordable coverage available, full stop. Medicaid is not expanded in South Carolina.
If you don't
Full-price marketplace plans are the most expensive coverage in South Carolina. For healthy people, private PPOs on Cigna, Aetna and PHCS PPO are routinely 30–50% less. South Carolina 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.
South Carolina didn't expand Medicaid, and most marketplace plans here are narrow-network HMOs — which is why a national PPO is the thing self-employed buyers ask about first.