Commercial real estate rental rates are typically stated in terms of $/sf/year. Your calculation of ($5 x SF / 12) is correct, and $5/sf is very inexpensive real estate unless it is an industrial property.
You would pay the landlord on a monthly basis. The typical lease term on commercial space is usually 3-5 years, however, with the current economic conditions, landlords are often willing to cut a short-term deal to generate income for their property.
Mar 7, 2009