Most listings are in the $10's per square foot per year. The Shasta submarket is going through a a rise in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 9% increase in rent.
In the last 90 days, 20 listings have been listed, which means new availabilities are probably 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 1,200 sqft. Most properties in this market are around 2 floors. Most buildings in this region were built in 1990 and are Class B.