On average, listings lease in the $20's per square foot per year. The Gilroy region is seeing a an increase in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 11% increase in rent.
Compared to the rest of the Silicon Valley market, the Gilroy submarket has lower rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 39 listings have been made available, which means office spaces most likley are going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,450 sqft. Most properties in this market are around 1 floors. Most buildings in this area were built in 0 and are Class B.