Most listings are in the $0's per square foot per year. The Norristown region is going through a decline in rates. In the last 3 months, the median rate fell $24 per sqft per year. That's a 100% decrease in rent.
In the last 90 days, 1 listings have come on the market, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. 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 sqft. Most properties in this market are approximately 4 floors. Most buildings in this market were built in 1955 and are Class C.