Turns out you'll need a doctor's prescription to even order a plain cotton mattress. Yet another perfectly reasonable regulation from our friends in the California Legislature! :)
My least-favorite CA regulation has to do with eye-glasses. I lost my only pair and went in to get a replacement on a Saturday, but I couldn't because my (perfectly fine) prescription had expired. I had to make an appointment to get an exam in order to get new glasses, but they were closed for the weekend and booked for a few days.
So I spent about a week with headaches because some CA legislator decided it was in my best interest to pay some practitioner to get the same prescription for glasses every year.