On average, listings lease in the $20's per square foot per year. The Orange submarket is going through a decline in rates. In the last 3 months, the median rate fell $5 per sqft per year. That's a 16% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Orange region has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 64 listings have come on the market, so you'll want to check back regularly for new listings. 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 1,890 sqft. Most buildings in this region are around 2 floors. Most buildings in this market were built in 1981 and are Class B.