NEW YORK (MainStreet) — Many Americans are facing penalties because they have not signed up for health insurance and do not plan to purchase any this year.

One-third of Americans who don't have insurance do not plan to purchase any despite the Affordable Care Act's requirement that they obtain health insurance or pay a fine, according to a recent Bankrate.com report.

With the clock winding down, the administration has implemented a "grace period" for the Affordable Care Act to give consumers another opportunity to sign up.

While 41% of the uninsured respondents who plan to stay uninsured are choosing to do so because they think health insurance is too costly, a whopping 70% of uninsured Americans don't know about the subsidies available to reduce the cost of health insurance.

"This is a staggeringly high percentage," said Bankrate.com insurance analyst Doug Whiteman. "The government has spent over half a billion dollars promoting the Affordable Care Act and more than two-thirds of uninsured Americans still don't know about the subsidies."

"It is still disturbing that people still know so little," he said. "Health insurance is such a complicated topic to begin with. It doesn't surprise me that people are still confused."

While 66% of uninsured 18-29 year-olds say they will sign up for health insurance this month, another 28% say they will stay uninsured. Of those that will stay uninsured, 31% say they will do so because they are healthy and do not need health insurance.

Many consumers still mistakenly believe that missing the March 31 deadline equates to just paying a $95 penalty, said Carrie McLean, director of customer care at eHealth.com, an online health insurance exchange based in Mountain View, Calif. "We're finding from consumers calling into our customer care center that they don't understand what the March 31 deadline really means."

After March 31, consumers cannot purchase health coverage on their own until 2015 unless they have a qualifying event like marriage, the birth of a child or the loss of employer coverage.

For most consumers, the penalty will be a lot higher than $95 because the federal law states that it is $95 per adult or 1% of your income, whichever is greater. If you are earning $50,000 per year, your tax penalty could be $500, McLean said.

Respondents between the ages of 30 and 49 are the most likely to remain uninsured with 39% who plan to continue going without health insurance. Almost half in that age group who won't get insured or 47% cite cost as the biggest factor.

Consumers who are worried about the expense of health insurance need to find out information about how much premiums cost before they opt out of enrolling, she said. eHealth's Price Index reports average monthly premiums for individuals and families on a nationwide and state basis and can give you an estimate of what other people are paying for coverage by clicking here -

The average monthly premium for individual plans not including subsidies is $267 as of March 17 and $672 is the average monthly premium for family plans without subsidies, McLean said.

Some people will be able to qualify for an extension to sign up for insurance coverage on the federal exchange or www.healthcare.gov beyond March 31 if they indicate that they tried to enroll before the deadline, but were unable to because of technical problems, said John DiVito, president of Flexible Benefit, a Rosemont, Ill. private health insurance exchange. Two-thirds of all states have made their plans available on the government website.

"It appears this grace period will rely on the 'honor system' and the government is not going to make anyone provide documentation of when or how their difficulties began," he said.

Millions of uninsured consumers need to be prepared for the financial penalties they will face if they choose to forego healthcare enrollment, DiVito said. For those on a budget, these penalties will make quite a dent in their pocket.

Many people are also not considering the risk of going uninsured and the possibility of getting sick during that time. The average cost for treating an upper respiratory infection can amount up to $740, and consumers without insurance won't receive any help paying that bill, he said.

Some states are following the federal government with similar extensions, said McLean.

"These new dates can cause a lot of confusion in the marketplace, but it's important to remember that March 31 is still the deadline for open enrollment," she said. "We recommend that consumers take the time to understand the details behind these extensions so that they don't miss out on enrolling in coverage during this current enrollment period. Consumers may also subject to the tax penalty if they don't qualify for this special enrollment period and have not obtained minimum essential coverage by March 31 and keep it without a gap longer than three consecutive months."

--Written by Ellen Chang for MainStreet