Legal Question in Business Law in California

I agree that the fee is ridiculously high, but this isn't really a legal question. You can either pay the fee or not have a P.O. Box.

The USPS is a money-losing quasi-governmental organization. They are trying to minimize their losses, sometimes in some rather silly ways. I've had mail held back and notices written up and put in my box when 22c postage was due. I'm sure the clerk's time to write the notice, then deal with me at the counter to collect the 22c, cost the USPS at least a dollar. Nevertheless, rules are rules.