Little Chicago Pizza does a good job at what they do. They have a deal that includes two slices of cheese pizza and a soda for something like 4 bucks, and its tasty. Its a little rough around the edges - for example there's no napkin dispenser, just a stack of paper towels - but that's what makes it 'Little Chicago'. Slices are primarily for lunch and run out early in the evening, so don't expect to get any slices for dinner... however the pie prices aren't bad.
The last time I was there, I saw the philly steak and it was a monster! There's limited seating, and its a little grungy, so its probably not the place you want to schedule your kids birthday party, but for any native Chicagoans here in the valley - go check it out. The walls are painted with murals of the Chi-city, and the staff was extremely friendly.