On average, listings lease in the $30's per square foot per year. The California submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 3% decline in rent.
In the last 90 days, 9983 listings have come on the market, 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 consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,270 sqft. Most properties in this region are around 2 floors. Most buildings in this area were built in 1958 and are Class B.