Most listings are in the $20's per square foot per year. The Mesa submarket is experiencing a a rise in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 11% increase in rent.
Compared to the rest of the Phoenix Metropolitan Area market, the Mesa submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 182 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the available space in the Mesa are subleases, so you will probably have to consider a longer term lease. 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 1,330 sqft. Most buildings in this region are approximately 1 floors. Most buildings in this market were built in 1989 and are Class B.