Average cost of a house in America is around $380k, average cost of a house in San Francisco is $1.7M according to Zillow. San Jose is $1.2M. Fremont is $1.1M. The cheapest (and not a great place to live and horrible commute) place in the Bay Area is Vallejo and that's still $450k.
So 3-6x more expensive depending on where you look generally.