Most listings are in the $20's per square foot per year. The Anaheim submarket is going through a decline in rates. In the last 3 months, the median rate decreased $10 per sqft per year. That's a 30% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Anaheim region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 34 listings have come on the market, which means new availabilities most likley are going fast. You'll want to be prepared to make an offer immediately. About 6% of the available space in the Anaheim are subleases, so you will probably have to focus your search on direct office leases. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 3,250 sqft, there are still 0 listings below 2,000 sqft. Most properties in this region are approximately 2 floors. Most buildings in this area were built in 1983 and are Class B.