On average, listings lease in the $20's per square foot per year. The Gilbert region is going through a a boost in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 3% rise 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 discounted submarket.
In the last 90 days, 38 listings have come on the market, which means spaces are probably going fast. You'll want to be prepared to tour spaces as quick as possible. About 5% of the listings 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 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 1,480 sqft. Most buildings in this area are around 2 stories. Most buildings in this region were built in 2006 and are Class B.