The cheapest land on which you could build a yurt or small cabin (illegally) in Berkeley I found on realtor is 60k (it is pending sale). The cheapest house is well north of 200k. You could build your own yurt or cabin for only 10 grand. You're joking yourself if that isn't very cheap by comparison.
[1] https://www.realtor.com/realestateandhomes-detail/55-Panoram...