Most listings are in the $20's per square foot per year. The Denver County submarket is going through a decline in rates. In the last 3 months, the median rate fell $3 per sqft per year. That's a 8% decline in rent.
In the last 90 days, 344 listings have been made available, so you'll want to check back regularly for new listings. About 6% of the office spaces in the Denver County are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 properties in this market are around 5 stories. Most buildings in this region were built in 1976 and are Class B.