Most listings are in the $30's per square foot per year. The El Paso de Robles submarket is experiencing a an increase in rates. In the last 3 months, the median rate went up $4 per sqft per year. That's a 13% rise in rent.
In the last 90 days, 9 listings have been posted online, which means spaces most likley are leasing quickly. 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 600 sqft.