There are a lot of adds including signs on the side of the road for health insurance for the self employed. Does anyone have some experience with them.

I don't have any experience with them but using Google may help you.

Have a great day and God bless.

Mega Life, Mid-West National Life of Tennessee and Chesapeake Life are all divisions of UICI/Health Markets. These companies sell health and life insurance. In most states you have to join an association NASE or Alliance for Affordable Services to purchase health insurance. These are also UICI companies. I think that if you have to buy into one of the associations to get insurance should be considered as part of the cost of the insurance.
In general the companies offer a variety of health plans and within each plan various levels of deductibles. The plans are primarily for hospitalization with additional cost riders to get non-hospital benefits. This lets you "tailor" the plan to need you unique needs. They have sold on the idea that there is no pre-authorization for benefits.
One key issue that you should consider is how the plan's deductible works and what expenses that you are responsible for that do not apply to the deductible. In the past the plans have require had per illness or injury deductibles and 3 deductibles to be met before you can expect the plan to cover 100% of costs of subsequent plans. Non-hospitalization/surgical expenses have not counted towards the deductible.
Read any policy completely during your free look to see how the deductibles work, the definition of "Medical Necessity" and see if they still effectively have "post-authorization". I am a former agent and policy holder, but dropped out because I did not feel comfortable with these issues.

Chuck, I am self employed and therefore self insured and I checked into Mega Life. I didn't like that they wouldn't give me a quote over the phone, and required I meet with a sales person. I also didn't like that their local sales force seems to be mostly part time retirees and stay at home parents doing it for extra money. I spoke to two and had to listen to one lady's child screaming in the background. The whole process just felt like a multi-level marketing thing (not that it is that, just felt like that) rather than hiring professionals.

Also, I heard from a few people that they got in at incredible premiums, only to have them raised 100% over the course of 2 years.

I ended up with my state's Blue Cross/Blue Shield and got a pretty comprehensive plan and excellent rate. I was able to view their rates and plans and apply right online.