The typical asking rate per listing is in the $20's per square foot per year. The Portland submarket is experiencing a decline in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 4% decrease in rent.
In the last 90 days, 40 listings have been listed, which means new availabilities are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 13% of the available leases in the Portland 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.
The standard measurement for office space in this area is around 1,500 sqft. Most properties in this area are approximately 3 stories. Most buildings in this market were built in 1900 and are Class B.