Compared to the rest of the Seattle Metropolitan Area market, the Sumner region has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 2 listings have come on the market, which means spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 200% of the listings in the Sumner 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 posted, so finding a space for a small business might be tough.
Even though the median size is 4,000 sqft, there are still 0 new listings below 2,000 sqft. Most buildings in this market are approximately 1 stories. Most buildings in this market were built in 2001 and are Class B.