On average, listings lease in the $20's per square foot per year. The Renton submarket is going through a an increase in rates. In the last 3 months, the median rate rose $29 per sqft per year.
Compared to the rest of the Seattle Metropolitan Area market, the Renton submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 18 listings have been made available, which means spaces are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 100% of the available leases in the Renton are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 2,650 sqft, there are still 0 new availabilities below 2,000 sqft. Most properties in this area are approximately 2 stories. Most buildings in this area were built in 1983 and are Class A.