The typical asking rate per listing is in the $20's per square foot per year. The Westminster region is experiencing a an increase in rates. In the last 3 months, the median rate went up $24 per sqft per year.
Compared to the rest of the Denver Metro market, the Westminster region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 33 listings have come on the market, which means office spaces most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 30% of the listings in the Westminster 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,400 sqft. Most properties in this area are approximately 2 stories. Most buildings in this area were built in 1990 and are Class B.