What are the ten cheapest cities in California?
No one has that answer because you have not defined cheapest, nor have you defined city. Some are big, some are small. However: Draw a line across the state at the level of Oroville and from there North to the border with Oregon, are 50 places where the Livin’ is Good and the prices for food and shelter are reasonable. Some are in the hills and mountains and a few are in the Big Valley. There are some others in the smaller Valleys that are inexpensive, but may not have all the refinements that you expect. So re-enter the question with more specifics if you truly are serious.