On average, listings lease in the $10's per square foot per year. The Spokane Valley submarket is going through a a rise in rates. In the last 3 months, the median rate rose $3 per sqft per year. That's a 17% increase in rent.
In the last 90 days, 45 listings have been listed, so you'll want to check back regularly for new listings. 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 1,300 sqft. Most buildings in this area are approximately 2 floors. Most buildings in this market were built in 1982 and are Class B.