The typical asking rate per listing is in the $30's per square foot per year. The Simi Valley submarket is going through a an increase in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 3% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Simi Valley submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 10 listings have come on the market, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 1,960 sqft. Most properties in this area are around 2 stories. Most buildings in this region were built in 1986 and are Class B.