The typical asking rate per listing is in the $30's per square foot per year. The Beaverton region is going through a an increase in rates. In the last 3 months, the median rate increased $5 per sqft per year. That's a 21% increase in rent.
Compared to the rest of the Greater Portland market, the Beaverton submarket has greater rates, and you'll need to make a great offer to be in this hot submarket.
In the last 90 days, 27 listings have come on the market, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 4% of the available leases in the Beaverton are subleases, so you will probably have to focus your search on direct office leases. 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 2,450 sqft. Most buildings in this market are around 1 floors. Most buildings in this area were built in 1987 and are Class A.