Most listings are in the $30's per square foot per year. The Simi Valley submarket is experiencing a a boost in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 8% rise in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Simi Valley submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 11 listings have been posted online, which means leases 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 posted, 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 buildings in this market are around 2 stories. Most buildings in this region were built in 1986 and are Class B.