The typical asking rate per listing is in the $20's per square foot per year. The San Luis Obispo submarket is going through a an increase in rates. In the last 3 months, the median rate rose $4 per sqft per year. That's a 17% increase in rent.
In the last 90 days, 51 listings have come on the market, so you'll want to check back regularly for new listings. About 2% of the available space in the San Luis Obispo are subleases, so you will probably have to consider a longer term lease. 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 1,250 sqft. Most properties in this market are close to 2 stories. Most buildings in this area were built in 2002 and are Class A.