On average, listings lease in the $30's per square foot per year. The Miami-Dade County region is going through a decrease in rates. In the last 3 months, the median rate fell $9 per sqft per year. That's a 22% decline in rent.
In the last 90 days, 362 listings have come on the market, so you'll want to check back regularly for new listings. About 4% of the available leases in the Miami-Dade County are subleases, so you will probably have to consider a longer term 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 1,910 sqft. Most properties in this region are around 3 floors. Most buildings in this market were built in 1982 and are Class A.