The typical asking rate per listing is in the $20's per square foot per year. The Gilbert submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 10% decrease in rent.
Compared to the rest of the Phoenix Metropolitan Area market, the Gilbert submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 91 listings have been listed, so you'll want to check back regularly for new listings. About 1% of the available leases in the Gilbert 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 1,800 sqft. Most properties in this region are around 2 floors. Most buildings in this area were built in 2006 and are Class B.