Most listings are in the $10's per square foot per year. The Lower Allen region is going through a a boost in rates. In the last 3 months, the median rate increased $20 per sqft per year.
In the last 90 days, 3 listings have been posted online, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. About 33% of the listings in the Lower Allen 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 780 sqft. Most buildings in this area were built in 1986 and are Class B.