On average, listings lease in the $20's per square foot per year. The Eugene region is seeing a an increase in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 5% rise in rent.
In the last 90 days, 30 listings have been made available, which means listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 940 sqft. Most buildings in this area are approximately 2 stories. Most buildings in this area were built in 1984 and are Class A.