On average, listings lease in the $20's per square foot per year. The Boulder County submarket is going through a a rise in rates. In the last 3 months, the median rate rose $26 per sqft per year.
In the last 90 days, 317 listings have been made available, so you'll want to check back regularly for new listings. About 50% of the available leases in the Boulder County 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,000 sqft. Most buildings in this area are approximately 2 floors. Most buildings in this region were built in 1989 and are Class A.