Best method is to have your spouse work somewhere that provides health insurance for the family. I assume that is not your case, or you wouldn't be asking the question.

The cost of insurance is one of the toughest parts about being freelance.  You will save some money if you can be part of a group.  Check with your local Chamber of Commerce, they often have group rates available for members.  There are some regional plans that are just for people who are self-employed. Use Google as means to start your search. Depending on where you live, however, you might not be eligible.