Most listings are in the $10's per square foot per year. The Gresham submarket is going through a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 7% decline in rent.
Compared to the rest of the Greater Portland market, the Gresham submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 4 listings have been posted online, which means spaces are probably going fast. You'll want to be prepared to make an offer immediately. 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 2,200 sqft. Most buildings in this market are around 2 floors. Most buildings in this region were built in 1998 and are Class B.