The typical asking rate per listing is in the $20's per square foot per year. The Costa Mesa submarket is experiencing a a boost in rates. In the last 3 months, the median rate went up $6 per sqft per year. That's a 23% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Costa Mesa region has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 86 listings have come on the market, so you'll want to check back regularly for new listings. About 2% of the available space in the Costa Mesa are subleases, so you will probably need to consider the implications of signing a direct lease with the building. 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 1,650 sqft. Most buildings in this market are around 2 floors. Most buildings in this area were built in 1983 and are Class A.