On average, listings lease in the $30's per square foot per year. The San Marino submarket is going through a a rise in rates. In the last 3 months, the median rate went up $40 per sqft per year.
Compared to the rest of the Metropolitan Los Angeles market, the San Marino region has more expensive rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 2 listings have come on the market, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. 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 480 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this market were built in 1961 and are Class B.