On average, listings lease in the $10's per square foot per year. The Littleton region is seeing a an increase in rates. In the last 3 months, the median rate went up $14 per sqft per year.
Compared to the rest of the Denver Metro market, the Littleton region has lower rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 8 listings have been listed, which means leases are probably going fast. You'll want to be prepared to make an offer immediately. About 238% of the available space in the Littleton are subleases, so you might be able to snag a great spot on a short term. 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 2,000 sqft. Most buildings in this market are approximately 2 stories. Most buildings in this market were built in 1983 and are Class B.