On average, listings lease in the $20's per square foot per year. The Northern Liberties - Fishtown region is going through a a boost in rates. In the last 3 months, the median rate increased $22 per sqft per year.
Compared to the rest of the Philadelphia market, the Northern Liberties - Fishtown submarket has less expensive rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 2 listings have been listed, which means spaces are probably leasing quickly. 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.
Even though the median size is 3,150 sqft, there are still 0 listings below 2,000 sqft. Most properties in this region are close to 4 stories. Most buildings in this area were built in 1950 and are Class B.