Insurance © Hemera, age fotostock

Ryan Miller, 36, of Beaverton, Ore., discovered something interesting after a 2008 layoff: He could make more money freelancing as a Web developer than he could as an employee. But his dreams of starting a business ended when his stay-at-home wife Sarah, also 36, investigated their health insurance options.

The immediate problem was that she was pregnant with the second of their two children, now ages 7 and 4.

"My pregnancy would not have been covered," Sarah Miller said. "We could have extended our COBRA coverage," she said, referring to insurance available after separation from an employer. "But that only lasts 18 months . . . and I have an autoimmune disease."

Her disease was in remission (and remains so), but the fact she had a pre-existing condition would have made insurance difficult to get and prohibitively expensive unless their family were covered by an employer-provided group plan. So Ryan Miller looked for, and found, another 9-to-5 job.

Starting next year, however, insurers have to cover everybody and can't charge more for pre-existing conditions. The changes being wrought by the Affordable Care Act, colloquially known as Obamacare, have renewed the couple's desire to launch a business.

"I don't know a lot about how (health insurance exchanges) will work, but maybe we could do it now," Sarah Miller mused.

Economists predict the wider availability of coverage under health care reform will release many workers from "job lock," allowing them to consider:

  • Retiring earlier (rather than waiting until age 65 for Medicare coverage).
  • Shifting to part-time work.
  • Quitting a job altogether to start a new business.

Most workers will stick with their current jobs and current employer-provided coverage, but exactly how many will take the leap away from their companies is a big unknown.

Researcher Craig Garthwaite estimates 500,000 to 900,000 people will leave their employers for various reasons because of improved health insurance availability. Garthwaite, an assistant professor of management and strategy at the Kellogg School of Management at Northwestern University, used a brief experiment with universal coverage in Tennessee to calculate the number.

Other researchers put the figure higher. A joint study by The Urban Institute's Health Policy Center and Georgetown University's Health Policy Institute predicted that health insurance reform will boost the number of self-employed people by 1.5 million.

Financial planner Michael Kitces thinks the impact will be profound, and has been encouraging other planners to talk to their clients about the new possibilities.

Image: Liz Weston

Liz Weston

"In having some of these conversations with advisers and their clients so far, it's been striking to realize just how much we've ingrained the idea that 'you have to have a job to get health insurance,' " Kitces said. "Now, whether the goal is to take some time off for work to train for a new career, retire early, start a new business, or go work for a small business that can't afford to offer health insurance itself, all of these options are on the table."

Of course, cost may still be an issue. Insurers will be allowed to base premiums on just four factors: age, location, family size and whether the insured people smoke. Federal subsidies will limit the total premium cost to 9.5% of household income for those with incomes under 400% of the poverty line (or $94,200 for a family of four). The Kaiser Family Foundation's subsidy calculator can help you figure out what your costs might be.

The 9.5% limit is pretty close to what many families pay now. Last year, the average employee's share of employer-provided coverage was $4,565, according to the Kaiser Family Foundation. With a household median income of just over $50,000, that would be about 9% of earnings.

That's still a chunk of change, and not one that everyone can afford. Those who earn more than 400% of the poverty level wouldn't get any subsidies, so their ability to give up employer-provided coverage will depend on how affordable the premiums will be. And that's not clear yet, since the health care exchanges that will offer the new coverage don't go live until Oct. 1. Some states are predicting steep increases for the more-inclusive policies required by the exchanges, while others, including New York and California, predict premium drops.

Also, a dream of starting a new business can be far different from the reality. Not everyone who's chafing as an employee is cut out to be an entrepreneur, and many of those who try to launch new businesses will fail.

But if all that's holding you back is access to health insurance, it may be time to start drawing up your business plan.

Click here to become a fan of MSN Money on Facebook

"I'd encourage anyone out there who's been struggling with their job or career to ask themselves: Would you still be working where you are today, if you had guaranteed access to health insurance?" Kitces said. "If the answer is no, then it's time to move past the job lock and explore the new opportunities that are becoming available."

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.

More from Liz Weston