Most listings are in the $30's per square foot per year. The Miami-Dade County region is going through a decline in rates. In the last 3 months, the median rate fell $12 per sqft per year. That's a 25% decrease in rent.
In the last 90 days, 377 listings have come on the market, so you'll want to check back regularly for new listings. About 4% of the office spaces in the Miami-Dade County are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 2,090 sqft. Most properties in this market are approximately 3 floors. Most buildings in this market were built in 1982 and are Class A.