On average, listings lease in the $10's per square foot per year. The Yakima region is going through a a boost in rates. In the last 3 months, the median rate rose $16 per sqft per year.
In the last 90 days, 12 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. 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 2,140 sqft. Most buildings in this area are approximately 2 floors. Most buildings in this region were built in 1998 and are Class A.