On average, listings lease in the $20's per square foot per year. The San Luis Obispo region is going through a a rise in rates. In the last 3 months, the median rate rose $28 per sqft per year.
In the last 90 days, 20 listings have been posted online, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 65% of the listings in the San Luis Obispo are subleases, so you might be able to find a shorter term or below market rent. 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 2,600 sqft, there are still 0 listings below 2,000 sqft. Most properties in this area are approximately 2 floors. Most buildings in this region were built in 2009 and are Class A.