I am not in CA, but I had to look for supplemental insurance and know exactly what you are talking about! The states are only required to make supplemental Medicare policies available to those who are 65 or over. I think I discovered that less than half of the states also require that supplemental be offered for disabled/under 65 folks. In AK, when I checked, the only alternative was called Sterling which would have cost something like $300-400/mo just for supplemental. There are many things that are covered under state Medicaid that are not covered under Medicare. If your disability income is low enough, or if your disability is set up in conjunction with what they call a "Miller Trust" (ie. In an income cap state), you may qualify for your state's Medicaid coverage as secondary insurance coverage to your Medicare.  Under this scenario, you probably have the best coverage. I was unable to find anything that was affordable and capable of supplementing Medicare in any reasonable, affordable manner. The only other alternative (which is not an alternative for older singles) would likely be if you have the option of being carried on your parent's or spouse's insurance and can use it as secondary coverage. I walked away from the issue feeling as if it was another place the disabled are slighted and perhaps an area that needs to be looked at more closely by advocates, NGOs, etc. Who represent the disabled. Good Luck!!