The typical asking rate per listing is in the $20's per square foot per year. The Spokane region is going through a a boost in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 10% increase in rent.
In the last 90 days, 114 listings have come on the market, so you'll want to check back regularly for new listings. About 3% of the listings in the Spokane are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 1,800 sqft. Most properties in this market are around 2 floors. Most buildings in this region were built in 1967 and are Class B.