Most listings are in the $30's per square foot per year. The California region is experiencing a a rise in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 8% increase in rent.
In the last 90 days, 9975 listings have been made available, so you'll want to check back regularly for new listings. About 5% of the available space in the California are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,310 sqft. Most properties in this market are close to 2 stories. Most buildings in this region were built in 1958 and are Class B.