The typical asking rate per listing is in the $50's per square foot per year. The Silicon Valley region is going through a a boost in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 3% increase in rent.
In the last 90 days, 819 listings have been listed, so you'll want to check back regularly for new listings. About 15% of the office spaces in the Silicon Valley are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 2,520 sqft, there are still 0 spaces below 2,000 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this region were built in 1982 and are Class A.