Pizza Pit in Sun Prairie is our go-to place for inexpensive pizza, especially at lunch time. Don't compare them to the expensive, gourmet place across the street -- but if you are looking for efficient service and a great value for the (low) price point, I strongly recommend The Pit. They sell pizza by the slice over the lunch hour (maybe all day? Not sure?) and that's a screaming deal.
They also offer gyros, which I've never tried.
Note that the owner is often there. He's a gruff guy, but takes a lot of pride in his pizza. Yes, this restaurant is locally owned and operated -- another reason to bring them your business.
p.s. They deliver. Remember to tip your driver!