The typical asking rate per listing is in the $30's per square foot per year. The La Mirada submarket is going through a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 2% decrease in rent.
Compared to the rest of the Metropolitan Los Angeles market, the La Mirada region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 7 listings have been made available, 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 880 sqft. Most buildings in this region are close to 1 floors. Most buildings in this area were built in 1988 and are Class A.