The typical asking rate per listing is in the $40's per square foot per year. The Iselin region is going through a a rise in rates. In the last 3 months, the median rate rose $46 per sqft per year.
In the last 90 days, 26 listings have been made available, which means leases are probably going fast. You'll want to be prepared to make an offer immediately. About 8% of the available leases in the Iselin are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 24,440 sqft, there are still 0 new listings below 2,000 sqft. Most properties in this market are around 5 stories. Most buildings in this area were built in 1986 and are Class A.