On average, listings lease in the $20's per square foot per year. The Kent submarket is going through a a rise in rates. In the last 3 months, the median rate rose $5 per sqft per year. That's a 33% rise in rent.
Compared to the rest of the Seattle Metropolitan Area market, the Kent region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 9 listings have been listed, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. About 11% of the listings in the Kent are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
Even though the median size is 8,500 sqft, there are still 0 office spaces below 2,000 sqft. Most buildings in this area are approximately 2 stories. Most buildings in this market were built in 1986 and are Class A.