Most listings are in the $30's per square foot per year. The Lucas Valley-Marinwood region is going through a a boost in rates. In the last 3 months, the median rate went up $36 per sqft per year.
Compared to the rest of the Bay Area market, the Lucas Valley-Marinwood region has smaller rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 5 listings have been made available, which means spaces might be going fast. You'll want to be prepared to make an offer immediately. 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 200 sqft. Most buildings in this region were built in 1980 and are Class A.