South Dakota residents shop for ACA health coverage through HealthCare.gov, the federal marketplace, since the state has not built its own exchange.
South Dakota expanded Medicaid after voters approved a ballot measure, so adults earning up to 138% of the federal poverty level generally qualify for coverage through the state's Medicaid program rather than needing a subsidized marketplace plan.
Because expansion is relatively recent in South Dakota, residents who were previously denied Medicaid under the old, narrower rules should check their eligibility again rather than assuming the earlier answer still applies. Marketplace shoppers in more rural parts of the state should also confirm network coverage before enrolling, since provider choice can be limited outside Sioux Falls and Rapid City.