On average, listings lease in the $30's per square foot per year. The Bellevue region is experiencing a a rise in rates. In the last 3 months, the median rate increased $8 per sqft per year. That's a 36% increase in rent.
In the last 90 days, 5 listings have been made available, which means new listings are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 20% of the available leases in the Bellevue 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.
The standard measurement for office space in this area is around 2,390 sqft. Most properties in this region are approximately 3 floors. Most buildings in this region were built in 2008 and are Class B.