Anywhere in central California (the central valley to be more specific) is cheap to live compared to SF. For example Madera, Fresno, or even Clovis you can rent a decent looking 3 bedroom house with yard for about $1000/month. However, these cities are mostly agricultural and do lack the "techy" feeling you'll find in bigger cities like SF or even LA. The summers are quite humid and hot, but it's nice that it only takes about 1.5 hours to drive up to Yosemite National Park.
Clovis, CA has a population of about 100k. Recently it has been trying to bring the technology atmosphere, for example a couple of days of go we had 59daysofcode conference (http://59daysofcode.com/). Quite exciting!