Most listings are in the $20's per square foot per year. The Toronto submarket is going through a an increase in rates. In the last 3 months, the median rate increased $28 per sqft per year.
In the last 90 days, 10 listings have been listed, which means leases might be leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 10% of the available space in the Toronto 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 1,620 sqft. Most properties in this market are close to 8 floors. Most buildings in this area were built in 1980 and are Class A.