Most people will likely have the subsidy sent directly to the insurer each month, Pearce said. But be aware: If your income goes up during the year, you might end up receiving a bigger subsidy than you're entitled to and have to return that overpayment to the government, she warned.

The cost-sharing subsidy reduces a consumer's share of medical costs and is available to those making less than 250 percent of the federal poverty level.

You must be enrolled in a silver plan in which the insurer picks up 70 percent of medical costs. The subsidy can reduce your share of the medical bills from 30 percent to 27 percent, 13 percent or as little as 6 percent, depending on your income.

Penalties Unless you don't have to file a tax return or fall into one of the other excluded categories, you will have to have health insurance next year or face a penalty. Parents, too, must make sure their young children are covered, Tolbert said.

In 2014, the penalty will be $95 per adult and $47.50 per child — with a family total of no more than $285 — or 1 percent of income, whichever is larger.

Penalties get bigger with time.

By 2016, the fine will be whichever is larger: 2.5 percent of income or $695 per adult and $347.50 per child, not to exceed $2,085 for a family. Thereafter, those dollar amounts go up with inflation.

You won't owe a penalty if you're without insurance for less than three months. And the penalty will never be larger than the national average cost for a bronze plan.

There's been much speculation about whether younger consumers might just pay the penalty and forgo coverage.

Young and healthy people are just one car accident way from thousands of dollars of medical bills, Quattrocki said.

"It may be cheaper, but you aren't getting health insurance," she said.

Maryland Health Insurance Plan This program was created years ago to provide coverage for residents unable to get insurance because of a pre-existing condition. The Affordable Care Act prohibits insurers from using pre-existing conditions to deny coverage.

About 21,000 Marylanders are in this plan, and around a third of them will be eligible for a federal subsidy to buy insurance and shifted to the exchange at the beginning of next year, Pearce said. The rest can remain in MHIP for now or go to the exchange.

Buying a policy The first payment will be made through the exchange, but thereafter premiums will be paid directly to the insurer. You must pay that first premium for the insurance to take effect.

To ensure coverage beginning Jan. 1, purchase insurance by Dec. 15, Pearce advised.

Wait longer, say Jan. 3, and the earliest that coverage will kick in is the first day of the next month.

Pearce predicted that there will be a surge of interest by consumers checking out the Maryland Health Connection in October. But she doesn't expect a jump in sales until early December by those wanting coverage starting in January and again in March, before open enrollment ends.

Visitors to the site might notice changes in the months ahead.

"What we go live with on Oct. 1 may not look the same as it does by the end of March because we will continue upgrading and making things better," Pearce said.