It depends on a number of factors, such as the state in which you live, the type of health plan you select, and your age.
To give you an idea, here is some general information on the average premiums that single people in the United States pay for health insurance.
According to the Kaiser Family Foundation's 2018 Employer Health Benefits Survey, the average premium for health insurance plans sold on the individual market was $623 per month. That figure is higher than the average premium for plans offered through employers, which came in at $569 per month.
That being said, the premium an individual pays for health insurance often varies based on their age and health plan. For example, according to a Fact Sheet from the Department of Health and Human Services, in 2018, the average single person in the United States who purchased a plan on the individual market paid $456 per month for a bronze plan, $568 per month for a silver plan, $697 per month for a gold plan, and $813 per month for a platinum plan.
Your age also plays a key role in the amount of your premium. Generally speaking, your premium will increase as you get older. The Department of Health and Human Services notes that in 2018, a single person in their 20s paid an average of $211 per month for a plan on the individual market, while a single person in their 50s paid an average of $526 per month.
In summary, the average premium for a single person in the United States depends upon many factors, such as place of residence, the type of health plan they choose, and their age. Generally speaking, plans sold on the individual market come with an average premium of $623 per month. That figure varies based on the type of plan and the individual's age.
I hope this gives you a better understanding of the average premiums that single people can expect to pay for health insurance.
For more information, please check out the KFF Employer Health Benefits Survey and the Fact Sheet from the Department of Health and Human Services.
https://www.kff.org/report-section/ehbs-2018-summary-of-findings/
https://www.hhs.gov/sites/default/files/individual-market-fact-sheet.pdf