In HealthCare.gov states, people who expect their annual income in 2023 will be no more than 150% of the federal poverty level ($20,385 for a single person, $34,545 for a family of 3) can apply for a special enrollment period (SEP) to sign up for coverage.

If you miss the Open Enrollment period, this low-income SEP will be available throughout the year. Go to HealthCare.gov and indicate that you expect your household income to be no more than 150% of the poverty level in 2023.  You will be able to sign up for coverage and subsidies right away, without having to prove you are eligible for this special enrollment opportunity. However, HealthCare.gov will automatically verify your income estimate, as it does for all applicants.  If the amount you attest to on your application is substantially different from income data the marketplace can check online, you might be asked to provide additional documentation within 90 days.

You can sign up for a plan in any metal level of coverage; but at your income you will be eligible for silver plans with small or no premiums and with cost sharing subsidies that dramatically reduce deductibles and copays. 

If you already signed up during Open Enrollment, and then your income falls to 150% of the poverty level, you can also use this SEP to change plans, though you will be limited to switching to a silver-level plan.  At your new lower income, silver plans will offer very low deductibles and copays. 

State-run marketplaces also have the option of offering this low-income SEP.