The typical asking rate per listing is in the $20's per square foot per year. The Casselberry submarket is going through a a rise in rates. In the last 3 months, the median rate increased $21 per sqft per year.
In the last 90 days, 10 listings have been posted online, which means spaces are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 60% of the available space in the Casselberry are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 1,500 sqft. Most buildings in this region are close to 1 stories. Most buildings in this market were built in 1986 and are Class B.