The typical asking rate per listing is in the $20's per square foot per year. The Milwaukie region is going through a a boost in rates. In the last 3 months, the median rate rose $26 per sqft per year.
Compared to the rest of the Greater Portland market, the Milwaukie submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 5 listings have been posted online, which means spaces might be going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,010 sqft. Most buildings in this region are around 2 floors. Most buildings in this market were built in 1988 and are Class B.