California is huge with many inexpensive places to live. However the coast and some of the more desirable interior are very expensive.

Pretty much anywhere in California that's a desirable place to live with reasonable job prospects has a high cost of living.

Those inexpensive places to live are inexpensive for a very good reason. They are often very unsafe and undesirable.

Everywhere good in California has been claimed :-(

Depends on your definition of undesirable. There are many remote, hilly towns if you enjoy nature and potentially living off-grid.

But yeah, if you're looking for sun, water sports & nightlife in CA, it's going to be very expensive.