The typical asking rate per listing is in the $10's per square foot per year. The Orange County region is experiencing a an increase in rates. In the last 3 months, the median rate went up $13 per sqft per year. That's a Inf% rise in rent.
In the last 90 days, 3 listings have been listed, which means new listings 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,000 sqft. Most buildings in this region were built in 1998 and are Class B.