Historically an arrangement for the rich, "concierge" medicine, as it is often called, is now available to people of average or modest means, including those on Medicaid and Medicare.

PPACA enables "direct primary care," although it does not free those participating in it from having to buy insurance. But for some people, buying a low-premium, high-deductible health plan and paying a doctor separately for primary care is less expensive than a traditional, high-premium insurance policy.

As a result, direct primary care has exploded.

Since Obamacare's passage in 2010, the number of direct primary care practices has increased from a handful to hundreds–Kaiser reports more than 400.

Some are skeptical that such an arrangement can truly work for low-income patients.

But Dr. Stanford Owen, a doctor in Gulfport, Miss., told Kaiser that he has many working-class patients. He charges $50 a month, but only after charging $225 for an initial visit and $125 for a follow-up visit.

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In Washington State, a network of direct primary care physicians has attracted 15,000 Medicaid beneficiaries. The company that operates the network, Qliance, touts unlimited physician visits and rapid online communication. 

"Medicaid patients are made to feel like they're a burden on the system," Dr. Erika Bliss, Qliance's CEO, told Kaiser. "For them, it was a breath of fresh air to be able to get such personalized care–to be able to talk to doctors over phone and email."

Similar arrangements are also underway for those enrolled in Medicare Advantage plans.