A reminder before everyone starts complaining about Pizza Hut in the comments: pizza is pizza and 50% off a large pizza is a deal I want to take when I need comfort food to sob into.
The link to your glorious half price pizza is here. The code in case you need it is HUT88272.
The deal's been going since the start of October and, to be frank, I'm disappointed I'm only seeing it just now. The good news: you still have a full week to gorge yourselves.
As for the pizza? I recommend sticking to the Pizza Hut designed ones. They know their ingredients and what works best I guess. What do I know, I like pineapple on pizza. I'm human trash.