I live in Tempe and I recently had my plate stolen, too. Actually, not only did they steal my plate and frame, but they gave me someone else's plate - complete with their license plate frame. How weird is that?
I called the police and they filled out a report (which you need to get another plate). You can print out a temporary 3-day restricted use permit online, which you print out and tape in your back window, for $1. Go to
https://servicearizona.com/webapp/permit3/start.do and follow the instructions. With this permit you can legally drive to and from work, etc., until you can get another plate (which is $5) at the MVD. I would definitely NOT drive without it, as the fines can be very hefty.
What an inconvenience, huh?