The typical asking rate per listing is in the $20's per square foot per year. The Boulder region is going through a an increase in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 5% rise in rent.
In the last 90 days, 228 listings have been made available, so you'll want to check back regularly for new listings. About 5% of the available space in the Boulder are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 2,900 sqft, there are still 0 listings below 2,000 sqft. Most properties in this market are around 2 stories. Most buildings in this area were built in 1984 and are Class A.