In Massachusetts, the penalty is set at up to half the cost of the lowest-priced plan available through the state-run insurance market. It kicks in when someone has been uninsured for more than three consecutive months. Annual penalties for 2012 range from $228 to $1,260, depending on income and age.

Nationally, the penalty is ­determined through a more complicated formula. It will start in 2014 at $95 or 1 percent of an individual’s income that year, whichever is higher, rising in the following years but with certain caps. In 2016, the tax penalty will be the higher of $695 or 2.5 percent of a person’s income.

That means federal penalties will be larger than the state’s for many people. The state has not determined what will happen to its penalty structure under the federal law, said Richard Powers, spokesman for the Massachusetts Health Connector Authority, one of the agencies overseeing compliance with the Affordable Care Act. The Legislature may decide the issue, he said.

For many across the country, paying the penalty may be less expensive than buying coverage. But the penalty is money lost, while people ostensibly get something in return for buying coverage.

Plus, people in this “God-fearing, tax-paying society” are prone to obey the law, said ­Amitabh Chandra, a health economist at the Harvard School of Public Health.

“It’s really the moral suasion of the mandate and the fear of the tax that gets people to comply with it,” Chandra said.

Erica Brunner of Jamaica Plain was 27 and working as a waitress in Brookline when she went without insurance for about five months in 2011. Her employer offered coverage, but at about $200 per month, she could not afford the employee contribution, she said. She knew she would be fined come tax time and paid a penalty of about $68.

Now, she works as a grant coordinator for Health Care for All, a consumer advocacy group that helps people — Machado among them — get coverage. She said she often talks with friends about options for coverage to avoid the penalty.

“I know what it’s like to be young and underemployed and be confused about what was available,” said Brunner, who enrolled in her new employer’s health plan because the nonprofit covered more of the premium and she had a larger, stable paycheck.

Joshua Archambault, director of health care policy at the Pioneer Institute in Boston, said other states should be wary of using Massachusetts’s experience as a benchmark. Massachusetts had a high rate of coverage before the 2006 state health law took effect, about 94 percent among adults not ­enrolled in Medicare compared with about 98 percent today, accord­ing to a state survey. Culturally, coverage is expected here, Archambault said.