Never thought I’d see pizza at Subway, but our local one started selling it this week. They bring out this frozen pizza (“Eat Fresh”?) and you can pick from pepperoni, sausage, extra cheese, I think each of those adds 25 or 50 cents. Then they pop it in the quick-cook oven, and you can get whatever normal Subway toppings on it you like. I got tomato slices on mine.
It was good, but it cost $4-something. IIRC the Pizza Hut personal pans are less than $3.
I bet Subway is trying to keep up with Quizno’s, which introduced a flatbread pizza a while back. I don’t think it’s frozen, though.
They first test-marketed these in San Diego about 5 years ago. I loved them and was sad when they went away. Haven’t had one since they’ve come back, but i’ll get around to it eventually.
I think most chain restaurant pizza sucks, but the technology involved here is interesting. Subway Restaurants use TurboChef ovens to cook the pizzas. They use convection and microwave technology to allow the pizza to be ready quickly. They’re also selling a home version of the oven, that, according to a review in the New York Times, allows one to roast a chicken in 15 minutes. The big downside is the $6,000 cost.
My son and I luvv Subway’s pizza! Yum! 
I used to work in a gas station with a subway in it years ago. When we were bored, we’d take the subway bread dough, cheese, marina from the meatball subs, and all of the various vegetables to make pretty good pizzas in the bread oven.