Most listings are in the $20's per square foot per year. The Modesto submarket is going through a a rise in rates. In the last 3 months, the median rate went up $3 per sqft per year. That's a 17% increase in rent.
In the last 90 days, 29 listings have been listed, which means leases most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 3% of the office spaces in the Modesto are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 1,860 sqft. Most buildings in this area are approximately 1 floors. Most buildings in this region were built in 1981 and are Class B.