“I’ve had one doctor appointment since I got this insurance, and I had to pay $60,” Ms. Shabazz told Daniel Flynn, a counselor with the health network, the Health Federation of Philadelphia. “I don’t have $60.”

Mr. Flynn spent almost two hours going over her Independence Blue Cross plan, which he explained had a “very complicated” network that grouped doctors and hospitals into three tiers. Ms. Shabazz, who has epilepsy, had not understood when she chose the plan that her doctors were in the most expensive tier.

“None of that was explained when I signed up,” she said. “This is the first I’m hearing it.”

Many people who signed up for private coverage through the new marketplaces had never had health insurance, and even the basics — like what a premium is and why getting a primary care doctor is better than relying on the emergency room — are beyond their experience. Others have a sense of how insurance works but find the details of the marketplace plans confusing, especially if they signed up without the help of someone who understood them.