As mentioned above, the majority of Americans who have insurance obtain it through employer-sponsored, or group health insurance plans. The coverage has numerous advantages – among them cost (including the government income tax exemption for health benefits), ease of enrollment, and a wide range of plan options. (In addition to a health insurance plan, employees may have the option to purchase insurance for dental, life, short- and long-term disability.) Read here for more details about group health insurance plans.
If the coverage available through your employer feels unaffordable, you can shop around online to see what's available. You may be able to find an individual market policy that will provide you with the coverage you need but is less expensive than the premium you pay at work. This is unlikely to be the case if your plan only covers yourself, since your employer is likely subsidizing a good chunk of the total premiums for the plan offered through your job. But some employer-sponsored plans require the employee to cover the full cost of adding family members, so it's possible that your family members could get a better deal with a separate policy.