The Arizona state sales tax rate for most retail purchases is 5.6% (effective June 1, 2013). Maricopa County adds on .7% sales tax to support roads and jails. That's a total of 6.3%. Then, each city may add sales tax. If you add the total of the Arizona sales tax and Maricopa County sales tax, 6.3%, to the city sales tax rate, you'll get the total retail sales tax that you'll pay when purchasing merchandise in that city.