Yes up river from Kernville
If you head up past lower peppermint, there is a camping spot called Lloyd Meadows. There are no restrooms and it is not on Google maps but it is free
If you are entering an official "campground" more than likely you'll need to pay. I have not heard of any free camping. I would recommend to go to recreation.gov and seek out a cheap campsite, you may end up paying $25 per night for single 8 person max campsite.
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