Millions of Americans gripe about the Affordable Care Act (a.k.a Obamacare, or ACA), and a small but growing number are doing something about it. According to the Washington Post, thousands are opting out of the ACA in favor of alternative health care options.

These insurance plans range from Christian co-ops and membership-based primary care clinics to disease-specific insurance policies and fixed-benefit plans. Their coverage is often cheaper than plans sold online in the ACA marketplace, but they may offer far less comprehensive coverage and contain far more restrictions than government-approved programs.

For example, even the most comprehensive free-market insurers reject people with pre-existing conditions and fail to include items such as mental health care, birth control and maternity coverage. The opt-out plans also vary widely in terms of their legality; as such, their members might have to pay the ACA’s penalty for having inadequate coverage. (The fine currently runs at $95 or 1 percent of a person’s total annual income, whichever is higher.)

Health insurance advocates also say the cheaper plan’s up-front savings could end up leaving patients with huge medical bills if they actually do get sick. If that happens, members cannot legally turn to state insurance departments to resolve their pricing disputes. Instead, they would have to negotiate directly with hospitals to reduce their bills, which is similar to what they’d have to do if they were completely uninsured.

For more information about navigating health insurance under the ACA, click here.

And for a doctor’s personal diagnosis of our health care system, click here.