On average, listings lease in the $20's per square foot per year. The Tustin region is experiencing a an increase in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 6% rise in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Tustin submarket has smaller rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 33 listings have been listed, which means new listings 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,440 sqft. Most properties in this area are close to 2 stories. Most buildings in this region were built in 1981 and are Class B.